How much fish can I put in a 29 gallon tank?

When stocking a 29 gallon aquarium, the two most important factors to consider are the adult sizes of the fish you want to keep and the total bioload that the tank can handle. The “one inch of fish per gallon” rule is too simplistic and often leads to overstocking smaller tanks. A better approach is to choose fish appropriate for the tank size, factoring in their adult sizes, activity levels, behaviors, and waste output.

Quick Overview

Here are some quick answers to common questions about stocking a 29 gallon tank:

  • A good general guideline is 1-2 small fish (under 2 inches adult size) per 5 gallons.
  • Medium sized fish (3-4 inches) should be kept to 1 per 10 gallons.
  • Large fish (over 4 inches) are usually not suitable for a 29 gallon tank.
  • Active schooling fish like tetras need to be kept in larger groups (6+) in a tank this size.
  • Territorial or aggressive fish like cichlids may not be suitable for a 29 gallon community tank.
  • Bottom dwellers like plecos and corydoras have lower bioloads and can be added in moderation.
  • Invertebrates like shrimp and snails have very low bioloads.
  • Live plants can help absorb waste and nutrients.
  • Heavily stocked tanks require more frequent water changes and tank maintenance.

Stocking Considerations

When planning out fish for a 29 gallon tank, the three major factors to consider are:

  1. Adult Size of Fish
  2. Schooling Needs
  3. Behaviors and Compatibility

Adult size is important because fish grow and small fish bought at the pet store will get bigger in your tank. You need to know the fully grown size of fish you choose and plan tankmates accordingly. Small nano fish under 2 inches are best for a moderately stocked community tank. Medium fish from 2-4 inches can work but with a lower total number. Large fish over 4 inches adult size are best avoided in a 29 gallon.

Schooling fish should be kept in proper sized groups (6+ is best) in this size tank. This allows them to exhibit natural behaviors. Tetras, rasboras, danios and small barbs are good escoling choices. Avoid solitary fish like bettas or puffers in a community 29 gallon.

Behaviors like territoriality and aggression must also be accounted for. Cichlids and gouramis may claim territories and harass more peaceful community fish in a 29 gallon. Research species carefully and avoid mixing aggressive fish.

Stocking Levels

Here are some examples of conservative, moderate and heavily stocked 29 gallon tanks:

Conservative Stocking

  • 10 Neon Tetras
  • 6 Harlequin Rasboras
  • 6 Corydoras catfish
  • 1 Bristlenose Pleco

This would be lightly stocked, with small schooling fish and bottom dwellers. Excellent for beginners!

Moderate Stocking

  • 12 Cardinal Tetras
  • 8 Rummynose Tetras
  • 6 Panda Corydoras
  • 6 Kuhli Loaches
  • 2 German Blue Rams

More fish with additional schools and species. The German rams may breeding and claim some territory.

Heavily Stocked

  • 12 Zebra Danios
  • 10 Serpae Tetras
  • 6 Pearl Gouramis
  • 5 Platies
  • 5 Kribensis
  • 3 Otocinclus

Multiple schools, medium sized fish, and several cichlids make this a lot of fish for a 29 gallon. Would require diligent tank maintenance.

Other Livestock

Invertebrates like shrimp and snails can be safely added to many community tanks. They have a very low bioload compared to fish and help clean up algae in the tank. Some popular options include:

  • Red Cherry Shrimp
  • Amano Shrimp
  • Nerite Snails
  • Mystery Snails
  • Ramshorn Snails

Avoid mixing shrimp with fish that may prey on them, like cichlids. Make sure to research any fish you plan to add and their compatibility with shrimp and snails.

The Importance of Research

When stocking any aquarium, researching potential fish is crucial. Don’t impulse buy fish based on appearance alone. Take time to learn about their adult size, behaviors, ideal tank conditions, and compatibility with other species. This will help you create a stable, thriving community tank.

Use reputable online resources and fish databases to research fish before buying them:

Your local fish store staff should also be knowledgeable about the fish they sell. Always ask questions and avoid impulse purchases. This will help make your 29 gallon tank a success!

Tank Setup and Filtration

Proper tank setup and filtration is key to maintaining healthy water parameters for fish. For a 29 gallon community tank, here are some recommended guidelines:

  • Filter sized for a 30-40 gallon tank or larger
  • Hang-on-back power filters, canister filters, and sumps can all work well
  • Heater capable of maintaining 75-82F temperature
  • Substrate like gravel, sand, etc.
  • Plants and decorations (driftwood, rocks, etc.)
  • Filtered lighting (fluorescent or LED)

Make sure to properly cycle your tank before adding fish. Read up on the nitrogen cycle and fishless cycling methods.

Perform regular partial water changes of 25-30% weekly, or more often on heavily stocked tanks. Test water parameters like ammonia, nitrite, nitrate and pH regularly.

Suitable Fish for a 29 Gallon Tank

Here are some examples of fish that can work well in a 29 gallon community tank:

Small Tetras

  • Neon Tetra
  • Ember Tetra
  • Rummynose Tetra
  • Cardinal Tetra


  • Harlequin Rasbora
  • Lambchop Rasbora
  • Glowlight Rasbora


  • Zebra Danio
  • Pearl Danio
  • Giant Danio


  • Cherry Barb
  • Checkerboard Barb


  • Threadfin Rainbow
  • Praecox Rainbow


  • Gardneri Killifish
  • Blue Gularis Killifish


  • Honey Gourami
  • Sparkling Gourami
  • Croaking Gourami


  • German Blue Ram
  • Kribensis
  • Apistogramma


  • Corydoras
  • Otocinclus
  • Small Plecos


  • Red Cherry Shrimp
  • Amano Shrimp
  • Nerite Snails
  • Mystery Snails

Remember to thoroughly research any fish species you are considering and make sure they are suitable for a 29 gallon community tank.

Tank Maintenance

Proper aquarium maintenance will help support the bioload of fish in a 29 gallon tank. Recommended guidelines include:

  • 25-30% weekly water changes
  • Testing water parameters 1-2 times per week
  • Cleaning/changing filter media monthly
  • Removing uneaten food and waste
  • Pruning plants as needed
  • Cleaning algae off decorations/glass

On more heavily stocked tanks, increase water changes to 30-40% twice per week. Monitor ammonia and nitrite closely and be prepared to act if levels rise.

Using a gravel vacuum to remove solid waste during water changes is recommended. Wipe down tank walls with an algae scraper or soft sponge as needed.

Clean or replace filter media like sponges, floss etc. monthly to maintain good biological filtration. Never rinse media in untreated tap water as it will kill beneficial bacteria.

Trim overgrown plants to keep the tank looking neat and prevent dying plant matter from fouling the water. Prune damaged leaves and remove any floating detritus.

Feeding Considerations

When feeding a community 29 gallon tank, keep in mind:

  • Small amounts of food multiple times per day
  • High quality foods designed for tropical fish
  • Soaked freeze-dried foods to prevent bloating
  • Variety of flakes, pellets, frozen and freeze-dried
  • Blanched vegetables like zucchini or spinach
  • Remove any uneaten food after a few hours

Cater to the needs of the species in your tank when feeding. Herbivores will need plant matter and algae. Carnivores require protein-rich foods like brine shrimp, bloodworms etc. Omnivores are not as picky but still need variety.

Only feed what fish can completely finish within a few minutes, 1-2 times per day. Uneaten food will degrade water quality. Target feed shy fish that don’t compete for food as aggressively.

Fast fish for 1 day per week to support digestion and overall health. This mimics natural conditions in the wild.

Plants for 29 Gallon Tanks

Live plants help absorb excess nutrients and provide habitat for fish. They also compete with algae for resources, helping control algal growth. Some easy plant choices include:

  • Java Fern
  • Anubias
  • Amazon Sword
  • Cryptocorynes
  • Java Moss
  • Vallisneria
  • Hygrophila
  • Rotala
  • Dwarf Sagittaria

Choose plants suitable for your tank conditions and complement the needs of your fish. For example, tetra species appreciate dense planting. Floating plants provide cover for fry and breeding fish.

Research plant care requirements carefully and provide supplemental fertilization as needed. CO2 injection can promote faster plant growth but is not essential in low-tech setups.

Tank Decor

When decorating a 29 gallon tank, keep these guidelines in mind:

  • Leave open swimming areas for active fish
  • Create sightline breaks with rocks, wood or plants
  • Allow 1-2″ between bottom of tank and substrate
  • Provide caves, overhangs and dense planting for hiding
  • Slope substrate towards the back for depth perception
  • Avoid sharp decor that could injure fish

Think about the natural habitats of your fish species and decorate accordingly. Provide open areas for schooling fish and breaks in line of sight to curb aggression.

Keep substrate 1-2″ from the bottom pane for effective waste capture and circulation. Vacuum open areas regularly.

Test water parameters more frequently after initially adding new decorations to ensure no leaching or water chemistry changes.


Successfully stocking a 29 gallon aquarium requires selecting appropriate fish, planning compatible species groups, providing proper tank maintenance, and researching the needs of fish before acquiring them.

Focus on smaller sized fish at moderate stocking levels. Supplement with cleanup crews of cories, shrimp and snails. Provide plenty of hiding spots and line of sight breaks.

Maintain steady tank conditions through regular testing, water changes, and filter maintenance. Remove waste promptly and monitor for aggression. Feed a varied diet in moderation.

A 29 gallon tank can make an excellent community aquarium when thoughtfully stocked. Take time to plan suitable inhabitants and you’ll be rewarded with a thriving, balanced ecosystem.

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