# 20 Gallon Fish Tank: Long vs High, Best Fish, and Setup A 20 gallon fish tank is the smallest aquarium that behaves like a real aquarium. It holds enough water to buffer small mistakes, it fits on a dresser or a desk, and it can support a genuine community of small schooling fish instead of one lonely specimen. The single most consequential decision you will make is not the filter or the light. It is the shape. A 20 gallon long gives you 30 inches of swimming length and roughly 12 inches of height. A 20 gallon high gives you only 24 inches of length but 16 inches of height. For almost every freshwater community you might want to build, the long wins, because fish swim horizontally far more than they swim vertically. This guide covers the dimensions and weight of both tanks, why footprint matters more than height, how to stock a 20 gallon tank with schooling groups and a centerpiece fish, which species to avoid, how to quarantine new arrivals, and how to maintain the system so it stays stable for years. **This article is educational and is not a substitute for veterinary diagnosis or treatment.** ## At a Glance | Decision | Recommendation | |--|--| | Best shape for a community tank | 20 gallon long (30 x 12 x 12 in) | | Best shape for a single tall-bodied or vertical species | 20 gallon high (24 x 12 x 16 in) | | Minimum cycle time before adding fish | 4 to 6 weeks with a test kit and ammonia source | | Schooling fish group size | 6 or more of the same species, 8 to 10 is better | | Centerpiece fish | One small cichlid, betta, or gourami, not a large "tank buster" | | Substrate | Sand or gravel, both fine, both with tradeoffs | | Water changes | 25 to 50 percent weekly, depending on stocking and nitrate trend | | Quarantine | Separate tank, 2 to 4 weeks observation before introduction | | Test kit | Liquid ammonia, nitrite, nitrate, and pH at minimum | ## Why the 20 Gallon Size Works A 20 gallon aquarium sits in a sweet spot. It is large enough that temperature and water chemistry do not swing wildly when you open the lid, and small enough that a weekly water change takes ten minutes with a bucket. It is also large enough to hold a proper school. The behavioral literature on ornamental fish makes clear that social species kept in inadequate group sizes or cramped quarters show disturbed behavioral repertoires, which reduces welfare and can impair health [1]. A 20 gallon long is the smallest standard tank that lets you keep a real school of six to ten small tetras or rasboras rather than a token pair. The tank also gives you room to build environmental complexity. Structural enrichment, including substrate and cover, changes both fish behavior and water chemistry, and the two cannot be separated [2]. More on that tradeoff below. ## 20 Gallon Long vs 20 Gallon High: Dimensions and Weight ### Standard Dimensions | Tank | Length | Width | Height | Footprint | Surface area | |--|--|--|--|--|--| | 20 gallon long | 30 in | 12 in | 12 in | 360 sq in | 360 sq in | | 20 gallon high | 24 in | 12 in | 16 in | 288 sq in | 288 sq in | Both hold the same volume, roughly 20 gallons of water, but they distribute it differently. The long spreads water across a wide, shallow rectangle. The high stacks it into a narrower, taller column. ### Why Footprint Matters More Than Height Three reasons. First, swimming space. Most small freshwater community fish, including tetras, rasboras, danios, corydoras, and livebearers, are midwater and bottom swimmers that move horizontally. They use length. Height above the level they naturally occupy is unused volume. Second, gas exchange. Oxygen enters water at the surface, and the surface area of a 20 gallon long is 25 percent larger than a 20 gallon high. That larger air-water interface supports more dissolved oxygen and more efficient carbon dioxide off-gassing, which matters in a small, heavily stocked tank. Third, territory. Bottom-dwelling and substrate-sifting species divide the floor into territories. A 30 inch floor gives you more usable real estate than a 24 inch floor, and the extra six inches often determines whether two corydoras groups can coexist without constant friction. The 20 gallon high is not a bad tank. It is a specialized tank. It suits a single tall-bodied fish, a betta in a planted setup, or a vertically oriented aquascape. For a mixed community, choose the long. ### Weight Water weighs about 8.34 pounds per gallon in US units. Twenty gallons of water is roughly 167 pounds. Add substrate, rock, filter media, and the tank itself, and a fully set up 20 gallon aquarium commonly lands somewhere between 225 and 250 pounds. That load is concentrated on a small footprint, so the stand matters more than the tank. A 20 gallon long on a flimsy particleboard shelf will sag, crack, or tip. Use a stand rated for the load, level it, and place it away from direct sun and heating vents. ## Choosing the Tank and Stand Selection criteria, in order of importance: 1. **Shape.** Long for community, high only for a specific vertical species. 2. **Glass versus acrylic.** Glass resists scratching and is cheaper. Acrylic is lighter and clearer but scratches easily. 3. **Rim versus rimless.** Rimmed tanks are cheaper and tolerate minor imperfections. Rimless tanks look cleaner but demand a perfectly level stand. 4. **Stand load rating.** Buy a stand rated above your calculated total weight, not at it. 5. **Lid.** A lid reduces evaporation, keeps fish in, and keeps cats and children out. Do not place a 20 gallon tank on furniture not designed for it. Water damage from a slow leak or a catastrophic failure is far more expensive than a proper stand. ## Filtration for a 20 Gallon Aquarium A 20 gallon tank needs biological filtration more than mechanical filtration. The nitrogen cycle converts toxic ammonia and nitrite into far less toxic nitrate, and that conversion is performed by bacteria living on surfaces, not by a cartridge you throw away [3]. Your filter's real job is to move water across a large colony of those bacteria. Recommended filter capacity for a 20 gallon tank is a rated flow of roughly 100 to 150 gallons per hour, which is five to seven turnovers per hour. Two common choices: - **Hang-on-back power filter.** Simple, cheap, easy to service. Use coarse sponge and ceramic or plastic biomedia. Rinse media in tank water, never in tap water, to preserve the bacterial colony. - **Sponge filter driven by an air pump.** Excellent biological surface area, gentle flow, ideal for bettas and fry. Less mechanical clarity. Canister filters are overkill for most 20 gallon setups but work well if you want high flow and hidden equipment. ### The Substrate Decision Substrate is not just decoration. It changes water chemistry. A controlled study of home-style freshwater tanks found that adding either gravel or sand increased pH and raised concentrations of total ammonia nitrogen and nitrate compared with bare tanks, and substrate was also associated with greater presence of Pseudomonas bacteria [2]. That is not an argument against substrate. It is an argument for managing it. Substrate provides surface area for nitrifying bacteria, gives rooting plants a medium, and offers foraging opportunities for species that sift or peck. It also traps organic waste if you never vacuum it. Sand versus gravel: - **Sand** suits corydoras, loaches, and other bottom feeders with delicate barbels. It compacts, so it needs periodic stirring or a Malaysian trumpet snail population to prevent anaerobic pockets. - **Gravel** is easier to vacuum and suits plants with strong roots. Coarse gravel can abrade the barbels of bottom-dwelling catfish. In marine and reef-adjacent systems, sand and live rock improve water quality and provide hiding places that reduce stress [3]. The same principle applies in freshwater. Cover reduces stress, and reduced stress supports immune function. ## Cycling a New 20 Gallon Tank Never add fish to a brand new tank. Cycle it first. The nitrogen cycle in a new aquarium: 1. Fish waste, uneaten food, and decaying plant matter produce ammonia. 2. Bacteria of the genus Nitrosomonas convert ammonia to nitrite. 3. Bacteria of the genus Nitrospira convert nitrite to nitrate. 4. Nitrate is removed by water changes and by plants. Ammonia and nitrite are toxic at low concentrations. Nitrate is far less toxic but accumulates and must be diluted. ### Step-by-Step Cycling 1. Set up the tank, substrate, filter, heater, and dechlorinated water. 2. Add an ammonia source. This can be a pinch of fish food that decays, or a pure ammonia product dosed to roughly 2 to 4 ppm. 3. Test daily or every other day for ammonia, nitrite, and nitrate with a liquid test kit. 4. Watch for ammonia to fall to zero while nitrite rises. 5. Watch for nitrite to fall to zero while nitrate rises. 6. When ammonia and nitrite both read zero within 24 hours of dosing, the tank is cycled. 7. Do a large water change to reduce nitrate, then add your first fish slowly. This usually takes four to six weeks. It can be faster if you seed the filter with established media from a healthy tank, and slower if the water is cold or the pH is very low. The ammonia and nitrite spikes during cycling are why fishless cycling is the standard recommendation. Fish-in cycling exposes animals to toxic nitrogen compounds, which is both a welfare problem and a disease risk. Stress from poor water quality is one of the recognized stressors in ornamental fish keeping, and stress suppresses immune function [4]. ## How Many Fish in a 20 Gallon Tank? There is no single correct number. The honest answer is that stocking depends on species, adult size, activity level, territoriality, filtration, and how diligent you are with water changes. The old "one inch of fish per gallon" rule is unreliable because it ignores body mass, waste output, and behavior. A 10 inch fish produces far more waste than ten 1 inch fish. A better framework: - **Schooling fish.** Six minimum, eight to ten preferred, of the same species. A single tetra is a stressed tetra. - **Centerpiece fish.** One, occasionally a bonded pair. - **Bottom dwellers.** A group of six or more small corydoras, or one small pleco species suited to a 20 gallon footprint. - **Total bioload.** Judge by your nitrate trend. If nitrate climbs above roughly 20 to 40 ppm between weekly water changes, you are overstocked or under-maintaining. ### A Worked Community Plan for a 20 Gallon Long This is a complete, balanced stocking plan for a 30 inch tank: - 8 to 10 small tetras or rasboras (midwater school) - 6 to 8 pygmy or small corydoras (bottom group) - 1 centerpiece fish, such as a single betta, a honey gourami, or a small Apistogramma - Optional: 1 small nerite snail or a few shrimp for algae control That is roughly 16 to 19 small fish in a well-filtered, well-maintained 20 gallon long. It sounds like a lot. It works because every fish is small, the groups are social, and the water changes are consistent. ### A Worked Community Plan for a 20 Gallon High The reduced footprint limits you: - 6 to 8 small tetras or rasboras - 1 centerpiece fish, such as a betta - Optional: 4 to 6 pygmy corydoras, if the floor space is not crowded Do not attempt two bottom-dwelling groups in a 20 gallon high. There is not enough floor. ## Best Fish for a 20 Gallon Tank ### Schooling Fish (Buy Six or More) - **Neon tetra and cardinal tetra.** Classic midwater schoolers. Cardinal tetras prefer warmer water. Both need a mature, stable tank. - **Harlequin rasbora.** Hardy, peaceful, tolerates a range of water parameters. - **Glowlight tetra.** Undemanding and long-lived. - **Ember tetra.** Very small, so you can keep a larger group. - **Chili rasbora.** Tiny and colorful, best in a planted tank. - **Celestial pearl danio.** Small, active, best in a group of eight or more. ### Bottom Dwellers - **Pygmy corydoras.** The best corydoras for a 20 gallon tank because of their small adult size. Keep six or more. - **Panda corydoras and other small Corydoras species.** Fine in a 20 gallon long, marginal in a high. - **Kuhli loach.** Nocturnal, hides well, needs a group and a soft sand substrate. ### Centerpiece Options - **Betta splendens.** One male, or one female in a community of peaceful tankmates. Bettas are territorial and should not be combined with other bettas. - **Honey gourami.** Peaceful, small, suits a community. - **Apistogramma species.** A single male or a bonded pair. They are cichlids and will defend a territory, so provide caves and plants. - **Bolivian ram.** A peaceful dwarf cichlid, but it needs floor space, so a 20 gallon long is better than a high. ### Livebearers - **Guppies, platies, and endlers.** Hardy and colorful. Guppies in particular are widely kept ornamental fish, and transport stress has been shown to increase their susceptibility to parasite infection [5]. Buy from a source that handles fish well, and quarantine. - **Important caveat.** Livebearers breed prolifically. A 20 gallon tank can go from six guppies to sixty in a few months. Plan for this or keep only males. ## Fish to Avoid in a 20 Gallon Tank - **Common pleco (Hypostomus plecostomus).** Grows to well over a foot. It will outgrow the tank and produce enormous waste. - **Goldfish.** Single-tailed goldfish grow large and produce heavy waste. They are coldwater fish and do not belong in a heated tropical community. - **Oscar, jack dempsey, and other large cichlids.** These reach 10 to 14 inches and need tanks of 55 gallons or more. - **Bala shark, iridescent shark, and tinfoil barb.** All grow far too large. - **Clown loach.** Reaches a foot and needs a group, which requires a much larger tank. - **Red-tailed black shark and rainbow shark.** Highly territorial as adults and need more length than a 20 gallon provides. - **Any fish sold as a "tank buster."** If the adult size exceeds roughly 3 inches, be skeptical. - **Multiple male bettas together.** They will fight. - **A single schooling fish.** A lone tetra or rasbora is a stressed animal, and stress impairs welfare and health [1]. ## Quarantine: The Step Most Owners Skip Quarantine is the single highest-value habit in fish keeping. A new fish can carry parasites, bacteria, and fungal infections that spread to your entire community. The stress of transport and introduction also suppresses immunity, which makes an outbreak far more likely [4][5]. ### Quarantine Protocol 1. Set up a separate small tank, ideally 5 to 10 gallons, with its own filter, heater, and a hiding place. 2. Add the new fish. Do not share nets, siphons, or buckets between the quarantine tank and the main tank. 3. Observe for two to four weeks. Watch for white spots, clamped fins, labored breathing, loss of appetite, stringy feces, and unusual behavior. 4. Feed lightly. Test ammonia and nitrite frequently because the quarantine tank is small and uncycled. 5. Change water as needed to keep ammonia and nitrite at zero. 6. If the fish remains healthy for the full observation period, move it to the main tank using a net that has not touched other tanks. If you cannot run a separate quarantine tank, at minimum isolate new arrivals in a large container with an airstone and observe them before introduction. This is a compromise, not a substitute. Transport itself is a stressor. Mechanical disturbance during transport has been shown to increase parasite burden in guppies, a globally important ornamental species [5]. Handle bags gently, float them for temperature, and acclimate slowly. ## Acclimation 1. Turn off the tank light. 2. Float the sealed bag for 15 to 20 minutes to equalize temperature. 3. Open the bag and add a small amount of tank water every 10 minutes for 30 to 45 minutes. This is drip acclimation and it matters most for sensitive species. 4. Net the fish into the tank. Do not pour bag water into the tank, because it may contain pathogens or high ammonia. 5. Leave the light off for the rest of the day. ## Plants, Decor, and Environmental Enrichment Environmental enrichment is not optional decoration. It changes behavior, reduces aggression, and improves welfare [1]. Fish in bare tanks show more stress behaviors, more aggression, and less natural foraging. Enrichment options for a 20 gallon tank: - **Live plants.** Java fern, anubias, cryptocoryne, and Amazon sword are undemanding. Floating plants like duckweed and salvinia provide cover and take up nitrogen. Floating macrophytes have been shown to reduce nitrogen compounds in eutrophic water, which supports their use as a biological nutrient export in aquariums [6]. - **Driftwood and rock.** Creates territories, caves, and grazing surfaces. - **Caves.** Essential for cichlids, plecos, and loaches. - **Dense planting.** Provides line-of-sight breaks that reduce aggression in community tanks. Plants also consume nitrate, which reduces the frequency and volume of water changes you need. ## Temperature, pH, and Water Parameters Most tropical community fish do well at 75 to 80 degrees Fahrenheit. Bettas prefer the upper end of that range. Corydoras and tetras are flexible within it. pH depends on your species. Most captive-bred community fish tolerate 6.5 to 7.5. Do not chase a specific pH with chemicals. Stable pH is more important than a specific number. A stable 7.4 is better than a fluctuating 6.8. General hardness and carbonate hardness matter for livebearers, which prefer harder water, and for soft-water species like discus and some Apistogramma, which prefer softer water. Test your tap water before choosing fish. ## Feeding Feed small amounts two to three times daily, or once daily with a fasting day. Overfeeding is the most common cause of water quality problems in small tanks. - **Flake and micro-pellet food** for midwater schoolers. - **Sinking pellets** for bottom dwellers. Corydoras need food that reaches the substrate. - **Frozen or live foods** such as brine shrimp, daphnia, and bloodworms as a supplement. Variety improves condition. - **Remove uneaten food.** It decays and produces ammonia. Diet composition affects water quality. Research on hybrid snakehead showed that replacing digestible starch with resistant starch improved nitrogen and phosphorus utilization and reduced nitrogen and phosphorus emissions into the water [7]. The practical lesson for aquarists is that what you feed affects what your filter has to process. High-quality, well-digested food produces less waste. ## Maintenance Schedule ### Daily - Observe fish for behavior changes, spots, clamped fins, or gasping. - Feed lightly. - Check temperature. ### Weekly - Change 25 to 50 percent of the water with dechlorinated, temperature-matched water. - Vacuum the substrate to remove trapped waste. - Rinse filter media in removed tank water, not tap water. - Test ammonia, nitrite, nitrate, and pH. - Trim plants and remove dead leaves. ### Monthly - Inspect the heater, filter, and air pump for wear. - Clean the glass and lid. - Check for algae growth and adjust light duration if needed. ### As Needed - Replace filter media only when it is falling apart. Replacing it wholesale destroys your bacterial colony. - Service the impeller if flow drops. Water changes are the backbone of aquarium health. A recirculating aquarium study demonstrated that ammonia and nitrite can be maintained at safe levels even without water exchange using advanced biofiltration and ozonation, but that system is not what a home hobbyist runs [8]. For a standard 20 gallon tank with a hang-on-back filter, water changes are how you remove nitrate and replenish minerals. ## Common Mistakes 1. **Adding fish to an uncycled tank.** This is the leading cause of new-tank fish death. 2. **Overstocking.** More fish means more waste. Judge by nitrate trend, not by counting. 3. **Overfeeding.** Uneaten food decays into ammonia. 4. **Buying a single schooling fish.** Social fish need groups [1]. 5. **Choosing the 20 gallon high for a community.** The footprint is too small for most mixed setups. 6. **Skipping quarantine.** One infected fish can wipe out a community. 7. **Replacing filter media.** You throw away the bacteria that keep the tank safe. 8. **Chasing pH with chemicals.** Stability beats a target number. 9. **Using tap water without dechlorinator.** Chlorine and chloramine kill nitrifying bacteria and harm fish. 10. **Ignoring a sick fish.** Early intervention is easier and more humane than late intervention. ## Troubleshooting ### Cloudy Water New tank cloudiness is usually a bacterial bloom and resolves on its own. Persistent green water is an algae bloom from excess light or nutrients. Reduce light duration, feed less, and increase water changes. ### High Ammonia or Nitrite Do an immediate 50 percent water change, reduce feeding, and test daily. If the tank is new, you are mid-cycle. If the tank is established, you may have overstocked, overfed, or lost your bacterial colony (for example, by rinsing media in tap water). ### High Nitrate Increase water change volume and frequency. Add fast-growing plants. Reduce stocking or feeding. ### Algae Balance light, nutrients, and plant mass. Six to eight hours of light daily suits most planted tanks. Floating plants shade the tank and compete for nutrients. ### Fish Gasping at the Surface This indicates low oxygen or high ammonia. Increase surface agitation, do a water change, and test. ### Aggression Add line-of-sight breaks, increase plant density, and check group sizes. A single fish of a schooling species is often the aggressor or the victim. ### Disease Signs White spots, velvet, fin rot, dropsy, and internal parasites all require treatment. Identify the problem before treating, because many treatments are species-specific and some are toxic to invertebrates, scaleless fish, and plants. ## Welfare and Safety Points Fish are sentient animals. Surveys of educated citizens in Bogotá and Curitiba found that roughly 70 to 80 percent of respondents perceived fish as sentient, and fish kept as pets were among the scenarios rated lowest for perceived suffering, which suggests that owners often underestimate the welfare needs of aquarium fish [9]. The practical implication is that the conditions you provide are the fish's entire world. Water quality, group size, tank shape, cover, and diet are welfare issues, not just aesthetic ones. The ornamental trade handles an enormous number of fish, and reported mortality rates during transport and handling vary widely, from as low as 2 percent to as high as 73 percent depending on the estimate [4]. Good handling, quarantine, and acclimation reduce that risk in your own tank. Where you source fish matters. Most freshwater ornamental fish sold in the trade are captive-bred, while the majority of marine ornamental fish are still wild-caught [10]. Captive-bred freshwater fish are generally hardier and better adapted to aquarium conditions. ## Limitations and When to Contact a Veterinarian This article is educational and is not a substitute for veterinary diagnosis or treatment. Individual fish, individual tanks, and individual disease presentations require individual assessment. Contact a veterinarian, ideally one with aquatic animal experience, when: - Fish show labored breathing, gasping, or hanging at the surface despite normal water parameters. - You see white spots, velvet, open sores, fin erosion, or a swollen body. - Multiple fish die within a short period. - A fish stops eating for more than a few days. - A fish shows abnormal swimming, buoyancy problems, or clamped fins that persist. - You are considering medication and are unsure of the correct product, dose, or duration for your species. - You keep invertebrates, scaleless fish, or plants alongside fish, because many treatments are not safe for them. - You cannot identify the problem after testing water and observing behavior. The World Aquatic Veterinary Medical Association (wavma.org) maintains resources for finding aquatic veterinary care. The Merck Veterinary Manual also provides reference material on pet fish health for owners and veterinarians. ## Frequently Asked Questions ### Is a 20 gallon long or a 20 gallon high better for a community tank? A 20 gallon long is better for nearly every freshwater community because it provides 30 inches of horizontal swimming length and 25 percent more surface area for gas exchange. The 20 gallon high suits a single tall-bodied fish or a vertical aquascape, not a mixed community. ### How many fish can I put in a 20 gallon tank? A well-filtered 20 gallon long can hold roughly 16 to 19 small fish if they are kept in proper social groups, for example 8 to 10 small tetras, 6 to 8 pygmy corydoras, and one centerpiece fish. Judge your actual stocking by your nitrate trend between weekly water changes, not by a fixed number. ### How long does it take to cycle a 20 gallon tank? Cycling usually takes four to six weeks. It is complete when ammonia and nitrite both read zero within 24 hours of adding an ammonia source and nitrate is rising. Seeding the filter with media from an established tank can shorten this. ### Can I keep a betta in a 20 gallon tank? Yes. A 20 gallon tank is an excellent home for a single betta, and a 20 gallon long allows peaceful tankmates such as small tetras or rasboras. Keep only one betta, because males fight and females can be aggressive toward each other. ### Can I keep goldfish in a 20 gallon tank? No. Single-tailed goldfish grow large, produce heavy waste, and are coldwater fish. They need much larger tanks and do not belong in a heated tropical community. ### Do I need to quarantine new fish? Yes. Quarantine new fish in a separate tank for two to four weeks before introducing them to your main tank. Transport and introduction are stressors that suppress immunity, and one infected fish can spread disease to your entire community. ### How often should I change the water in a 20 gallon tank? Change 25 to 50 percent of the water weekly, depending on stocking density and nitrate readings. Vacuum the substrate at the same time and rinse filter media only in removed tank water. ### Why is my 20 gallon tank water cloudy? New tank cloudiness is usually a harmless bacterial bloom that clears on its own. Persistent green water is an algae bloom caused by excess light or nutrients. Reduce light duration, feed less, and increase water changes. ## Related Articles - [Fish Tank Size & Stocking Calculator for Healthy Aquariums](/knowledge/veterinary-medicine/aquarium/fish-tank-calculator) - [Choosing the Right Tank Size and Stocking Your Aquarium](/knowledge/veterinary-medicine/aquarium-fish-care/tank-size-stocking) - [Fish Quarantine Tank Setup](/knowledge/veterinary-medicine/aquarium-fish-care/fish-quarantine-tank-setup) - [Betta Fish Tank Setup for Beginners](/knowledge/veterinary-medicine/aquarium-fish-care/betta-tank-setup) - [Best Fish for a Small Aquarium](/knowledge/veterinary-medicine/aquarium-fish-care/fish-for-small-tank) - [Tetra Fish Care: Species Guide, Tank Setup, and Feeding](/knowledge/veterinary-medicine/aquarium-fish-care/tetra-fish-care-species-guide-tank-setup-and-feeding) - [75 Gallon Fish Tank: Stocking Ideas, Weight, and Setup](/knowledge/veterinary-medicine/aquarium-fish-care/75-gallon-fish-tank-stocking-and-setup) - [55 Gallon Fish Tank: Stocking Ideas, Weight, and Setup](/knowledge/veterinary-medicine/aquarium-fish-care/55-gallon-fish-tank-stocking-and-setup) - [5 Gallon Fish Tank: Best Fish, Stocking Ideas, and Setup](/knowledge/veterinary-medicine/aquarium-fish-care/5-gallon-fish-tank-stocking-and-setup) ## Sources 1. [Understanding behaviour to improve the welfare of an ornamental fish.](https://pubmed.ncbi.nlm.nih.gov/34076258/) 2. [The Effect of Substrate on Water Quality in Ornamental Fish Tanks.](https://pubmed.ncbi.nlm.nih.gov/36230419/) 3. [EFFECTS OF SAND AND LIVE ROCK BOTTOM ON WATER QUALITY IN AQUARIUM TANK](https://www.semanticscholar.org/paper/bb26f6eb7485f92e667c08b468dcd711d51e3bc5) 4. [Stress and welfare in ornamental fishes: what can be learned from aquaculture?](https://pubmed.ncbi.nlm.nih.gov/28691234/) 5. [A neglected fish stressor: mechanical disturbance during transportation impacts susceptibility to disease in a globally important ornamental fish.](https://pubmed.ncbi.nlm.nih.gov/32132270/) 6. [THE USE OF FLOATING MACROPHYTES AS A BIOLOGICAL ALTERNATIVE FOR WATER QUALITY IMPROVEMENT IN EUTROPHIC ENVIRONMENTS](https://www.semanticscholar.org/paper/8123776246578e3f7f6ddaf06f4ef26be6840a60) 7. [Replacing starch with resistant starch (Laminaria japonica) improves water quality, nitrogen and phosphorus budget and microbial community in hybrid snakehead (Channa maculata ♀ × Channa argus ♂)](https://www.semanticscholar.org/paper/c4abbd8bf44908134a5736b6af1d093ef09c8c35) 8. [A potential zero water exchange system for recirculating aquarium using a DHS-USB system coupled with ozone](https://www.semanticscholar.org/paper/677cd6c4c0597e8143a49b0a1eb6896d9c91426e) 9. [Perception of Fish Sentience, Welfare and Humane Slaughter by Highly Educated Citizens of Bogotá, Colombia and Curitiba, Brazil.](https://pubmed.ncbi.nlm.nih.gov/28068372/) 10. [Wild caught ornamental fish: a perspective from the UK ornamental aquatic industry on the sustainability of aquatic organisms and livelihoods.](https://pubmed.ncbi.nlm.nih.gov/30671948/)