Bottom feeders are fish and other creatures that live and feed on the lower part of the aquarium. They can be a great addition to your tank and an unlikely match to your betta!
In this post, we’ll talk about the anatomy of bottom feeders, their feeding strategies, what are the best types, and whether they are good tank mates to betta fish.
Can Betta fish and bottom feeders be in the same tank?
Bottom feeders are fish and other creatures that find their food on or near the bottom of their habitats. But that doesn’t mean that all of them are detritivores (scavengers).
Some bottom feeders are herbivores or omnivores, eating algae and plants close to the substrate. Others can be detritivores, and some are carnivores and they can feed on other bottom feeders.
The anatomy of bottom feeders
Most bottom feeders exhibit a common body shape consisting of a flat ventral region. This enables their body to rest on the substrate, as well as move along the bottom of the tank. The degree of flatness of the ventral region can vary from mild like koi fish to extremely flat like stingrays, for example. One exception is the flatfish. Instead of having a flat ventral region, the flatfish are laterally depressed and lie on their sides.
Another specialized trait of the bottom feeder is their inferior mouth. This organ is located towards the bottom part of the fish’s body and is pointed downwards. The inferior mouth location helps bottom feeders to get their food from the substrate. Bottom feeders that have a more upward-pointing mouth usually feed on swimming prey. Some species of bottom feeders have a suckermouth that allows them to scrape algae and biofilms from surfaces.
Many bottom feeders have barbels which is a thin sensory organ similar to whiskers on the fish’s head but oftentimes they’re located close to their mouths. The fish’s taste buds are located in the barbels and this organ is also used for locating food in the bottom part of the water column. These specialized features help bottom feeders to survive in their typical environment without much competition.
Bottom feeders: The clean-up team
Bottom feeders are known to be low-maintenance organisms. They’re commonly known as the clean-up team due to their feeding strategies.
Detrivore bottom feeders feed off the dead organic material that is gathered from the water bodies down to the floor. Some bottom feeders like crabs can get detritus manually. Other species of bottom feeders will get their food by suspension feeding.
Carnivore bottom feeders can eat organisms like jellyfish and cephalopods. This allows the CO2 to be contained on the seafloor rather than be recycled back into the atmosphere. Bottom feeders that graze on algae help the plant to get their necessary light and nutrients, avoiding their competition.
The bottom line (no pun intended) is that in nature, the bottom feeder’s feeding strategy helps recycle the organic matter guaranteeing the water quality of their aquatic environments, and contributes to maintaining different biogeochemical cycles. Inside an aquarium, bottom feeders help keep the tank clean and the water parameters balanced since uneaten food will not get decomposed. Hence, the ammonia and nitrate levels won’t increase, potentially making your fish and other organisms sick.
Preparing your betta for the arrival of the new tank mate
Before adding a new tank mate to your betta’s tank you must consider the temperament of your fish. Each individual has their own temperament, but bettas are known to be aggressive towards other fish especially if they feel threatened somehow. If you already have a betta sharing a tank with another tank mate and they get along well, then you should be fine.
However, if your betta has lived alone for the most part of its life. Make sure you have a spare tank if things don’t work out between the new neighbors. Also, check whether the aquarium is big enough to have more than one tank mate. The more creatures living in the aquarium are not necessarily the merrier.
The betta can get stressed since they’re territorial fish. And in case there is no competition for food and territory, the chance of an ammonia buildup and poor water quality is high. So, think about what is the necessary volume of water that your betta needs, as well as each new addition. Is the current tank big enough? If not, it’s time to get a new one.
You can also try to introduce bettas to the new tankmates instead of the other way around. This way they won’t feel like there are other organisms trying to invade their territory but that they have a whole new realm to conquer! Ah, make sure that both water parameters and tank layout meet all tank mate requirements. Bettas like plants and hiding spots are a must. Bottom feeders like a layout with gravel, plants, moss, and for some, algae.
A very important thing to remember is that betta fish’s ideal pH is 7.0 and a temperature of 78 F (25.6 °C).
Bottom feeders for a betta tank
The following critters are known to be good tank mates to bettas:
Plecos are nocturnal and placid cave-dwelling fish native to South America. They are unlikely to engage in conflict unless it’s over their hiding spot. They feed mostly on plants and algae. Depending on the species, they can get up to 3 to 24 inches (4.7 to 61 cm). They need a large tank ranging from 30 to 125 gallons (110 to 475 L), a water temperature of 75 and 82 F (23.8 and 27.7°C), and a pH of 6.5 to 7.5. You will also need a great filtering system as plecos do produce a lot of waste.
Some small plecos (2 to 8 inches or 5.1 to 20.3 cm) that will make good companions for your betta are:
- Bristlenose Pleco;
- Green Phantom Pleco;
- Red Fin Dwarf Pleco;
- Clown Pleco;
- Mustard Spot Pleco.
Avoid big or colorful plecos like Sailfin pleco, Common pleco, and Gold Nugget Pleco.
Catfish are peaceful bottom-feeders and can be native to several parts of the world like Africa, Southeast Asia, Eurasia, and North and South America. They can be found in freshwater but the majority inhabit shallow, running waters.
Some species can hide under the substrate while others live in caves while others can be shoaling fish like Otocinclus catfish. These fish are happier living in a shoal of at least 10 specimens. They are also voracious algae eaters. Others, like Synodontis catfish, are nocturnal.
Depending on the species, they can live up to 10 years. Their water requirements can vary from temperatures from 70 to 78 F (21° to 25.5°C) and a pH of 6.5 to 8.2. The smallest species of catfish will do fine in a minimum of 20-gallons tank but beware of their adult size before deciding on a tank.
These are some of the catfish species that (1.5 to 10 inches or 3.8 to 25.4 cm) will do fine with your betta:
Avoid the species that can get a lot bigger than your betta. Some species can grow up to 5 feet (1.5 m)!
Corydoras are small bottom-dwelling fish native to South America but Panama. Although very peaceful, they’re actively shoaling fish and need to be in a group of at least 6 fish to be happy. They display various body shapes and coloration and their size vary from 1.0 to 4.7 inches (2.5 to 12 cm). Additionally, they have sharp mostly venomous spines that protect them from predators. They are scavengers, so avoid sharp substrates. Corydoras need a tank of at least 20-gallons with a temperature of 70 to 75 F (21.1°-23.8°C) and a pH between 6.0 and 8.0. Corys can live from 3 to 5 years. Here are some examples of corydoras for your betta tank:
- Adolph Corydoras
- Panda Corydora
- Three Stripe Corydoras
- Pygmy Corydoras
- Skunk Corydoras
- Arched Corydoras
- Peppered Corydoras
Loaches are bottom-dwelling fish found in rivers and creeks throughout Europe, Northern Africa, and Southeast Asia. They can be quite shy but some species can display aggressive behavior. Most of them have a long, thin, eel-like body. They can be as short as 1 inch (23 mm) like miniature eel-loach, to 20 inches (50 cm) long as the imperial flower loach. Some loaches are nocturnal, like khuli loaches. These are shoaling fish and need to be in a group of 5 or more loaches. Their tanks must be between 20 to 150 gallons (75 to 570 L), depending on their final size. The water temperature must range from 75 to 85 F (23.8°-29.4°C) and the pH from 5.5 to 7.0, depending on the species. Loaches can live from 10 to 20 years. These are betta-friendly loaches:
- Kuhli Loach
- Panda Garra Loach
- Horseface Loach
- Dojo Loach
- Reticulated Hillstream Loach
Try to avoid Yoyo loach, Skunk loach, Zebra loach, Angelicus loach and Clown loach. Although all of them are beautiful fish, they can get quite aggressive.
Freshwater shrimps are calm and mostly defenseless, so they have developed the ability to hide from bettas. Shrimps graze on algae, biofilm, moss, and some plants. Depending on their size, shrimps need a 10 to 30-gallon tank with lots of plants so they can hide. The tank parameter also varies from species to species, so you must research them beforehand. They can measure from 1 to 2.5 inches (2.5 to 5 cm) and live for a couple of years. Make sure you have a backup plan for their fry as shrimps breed quickly. These shrimps are good tank mates to betta:
- Red Cherry Shrimp
- Ghost Shrimp
- Amano Shrimp
The snails that will do well with bettas are mostly native South America, Southeast Asia, and Africa. They are peaceful creatures that feed on algae, biofilms, and uneaten food. Some of them, like the assassin snail, are carnivores. They can grow up to 1 to 2 inches (2.5 to 5 cm) and live for a year. Snails need at least a 10-gallon tank (37 L), with temperatures between 70 and 80 F (21 and 26.6°C), and a pH ranging from 6.5 to 8.0. Some species can eat plants or breed in freshwater. Make sure you research them before taking them home. These are some snails can get along with your betta:
- Assassin snails;
- Ramshorn snails.
Bottom feeders can be a great addition to your betta tank. Besides having a similar water parameter to a betta they are also very peaceful creatures towards a betta. They hide most of the time and can act as a clean-up crew, grazing on algae and uneaten food. Make sure you research the species to avoid surprises. Some bottom feeders like fish can get very big while other creatures like snails can over breed in freshwater.