Keeping anything in a 1 gallon tank comes with it’s challenges. The smaller the tank you have, the more unstable the water parameters are. However, if you add some live plants and are able to stabilize the water temperature, a 1 gallon tank can be the right size for certain critters. Even though a one gallon aquarium is too small to keep any fish, that doesn’t mean you are unable to keep anything in the tank. One thing to note though, if you plan on keeping more than one animal in the tank, you’re better off getting a slightly larger tank such as a 5 gallon. With that said, I have kept 3 out of the 5 animals on this list in a one gallon successfully.
Dwarf shrimp: There are many different varieties of dwarf shrimp you can find in fish stores now a days. Some are better suited for a small tank because they are hardier and more tolerant of water parameter fluctuations. Red cherries are among the hardiest as well as blue velvet shrimp. I would avoid the more delicate varieties like crystal red shrimp. Dwarf shrimp thrive in aquariums with live plants. They are a good choice for small tanks, because they don’t require a lot of food and don’t produce a lot of waste. This is especially important in such a small tank since too much food or waste can cause issues with water parameters. Another reason these are a good choice for a small tank is, it allows you to keep them in a species tank, safe from hungry fish that might snack on the babies. You could keep a small colony of shrimp in a one gallon tank. In fact that’s exactly what I have in my own one gallon tank.
Snails: There are a lot of different aquatic snails to choose from. Most snails that are readily available in fish stores, with the exception of the larger species like apple snails, can be great additions to a 1 gallon fish tank. Snails are a great part of a clean up crew and besides algae, they will eat extra food and dead or dying plant leaves. This helps keep your tank clean and stable. Some good snail candidates for a 1 gallon aquarium are, nerite snails, ramshorn snails, pond snails, and maylasian trumpet snails. Some people may consider the last three pest snails, but you can follow the link to read more about my take on these so called “pest” snails. I would personally only keep one or two nerite or ramshorn snails in a one gallon, whereas the pond or trumpet snails will breed and keep their population in check depending on the amount of resources available, aka food.
Dwarf crayfish: Dwarf crayfish have made their way into the hobby somewhat recently. They have similar care requirements as dwarf shrimp and can even be housed together. They tend to have fun personalities and can be pretty interesting. Unlike the common crayfish you’ve probably seen available often before, dwarf crayfish are actually peaceful and won’t dig up plants either. Even though they stay relatively small in size, between 1-2 inches, I would only recommend keeping one in a 1 gallon tank.
African Dwarf Frog: African Dwarf Frogs are a cool and unique animal you can potentially keep in a one gallon aquarium. In this size tank, you should really only keep one. You will also need to make sure to be more diligent about the water changes, since ADF’s produce more waste than the rest of the animals on this list. Since these little guys can jump out, it’s important to have a tight fitting lid.
I actually have sad story about this. I had one of these little guys in my tank at work once. The tank had a lid, but it wasn’t completely covered. One day I was looking in my tank and couldn’t find him. I later found out that someone found the frog all the way down the hall, but it was already dead. So moral of the story, make sure the top is completely covered. For more information on taking care of these little frogs, this is hands down the best resource I’ve found about them: https://www.myfroggycam.com/
Micro Thai Crab: These little guys are very new to the hobby and are also pretty rare. They are similar in care as the dwarf shrimp. Due to their small size, they’re actually perfect for a one gallon tank since on a larger tank, they tend to get “lost” and you won’t see them very often. These tiny crabs definitely need good water quality and do best in planted tanks. They forage for food in the plants and feel secure from predators when they can find hiding places among the plants. As previously mentioned, these are pretty rare, likely due to the fact they haven’t been successfully captive bred and are only found in one river in Thailand. If you are able to find them, you could keep a small colony in a one gallon tank.
For every animal on this list, you need to have a well established tank which should be setup for at least 1-2 months before adding any animals. This will give time for plants to grow and anchor themselves to the ground or a piece of driftwood. More importantly this will give the bacteria time to establish itself in the tank and for the tank to cycle.
Since a 1 gallon tank is so small, water changes are important. I’d recommend changing between 10-20% of the water either every week or every other week. You don’t need to disturb the substrate and I’ve even found a turkey baster can work pretty well for such small water changes.
Choosing the right animals for a one gallon aquarium is important if you want to be successful. Personally I think a good mix of snails and shrimp can make for an interesting one gallon aquarium especially if you add some live plants as well. The snails help keep the tank clean and the shrimp add pops of color and some activity. Whatever you decide to keep, always do your research on the animal to make sure you are caring for them properly.