Sucker fish are one of the most popular fish in the aquarium hobby for good reason! THey are hardy and unique looking, with prehistoric spines and hard scales that look rather fierce. Sucker fish also eat loads of algae, easing your chores if green decorations are an issue for you. However they also aren’t for every aquarium!
What are Sucker Fish?
Sucker fish is a broad label for the catfish in the family Loricariidae! All Loricariids are South American catfish with a downwards facing suction cup-like mouth. They use this to attach to leaves, driftwood, and other hard surfaces. Many evolved to hang onto hard surfaces in areas of strong water flow, like rapids and the region surrounding waterfalls.
Others live in slower bodies of water and use their round, toothy lips to rasp algae and biofilm from plants and rocks. Some are even carnivorous, feeding on invertebrates instead of vegetables!
Nearly all of the sucker fish you will encounter at the pet store are herbivorous since home aquariums are very good at growing algae. Algae thrives in bright lighting and high nutrient concentrations, both of which aquariums tend to have.
Fortunately, sucker fish can be a great way to reduce algae enough for you to keep up with it during regular aquarium maintenance!
Types of Suckermouth Catfish
When people ask about sucker mouth catfish they are usually talking about the Common Plecostomus. Raised by the thousands for the aquarium hobby, they are by far the most commonly bought sucker fish.
Unfortunately, the vast majority die because people don’t know all there is to their care. However, this care guide will spell out everything so yours will live a long and healthy life!
- Scientific Name: Hypostomus plecostomus
- Length: 18 to 24 inches
- Aquarium Size: 55+ gallons
Just as large but even more beautiful than the common black sucker fish is the Sailfin Pleco! They are becoming much more common in the hobby and have huge dorsal fins that catch your attention.
The only downside to keeping them is their size. Like the Common Pleco, Sailfin Plecostomus will need aquariums at least 55 gallons in size, with larger ones being better as they fully mature.
- Scientific Name: Pterygoplichthys Gibbiceps
- Length: 18 to 24 inches
- Aquarium Size: 55+ gallons
Bristlenose Plecos are some of the most interesting suction fish around! They have a bushy crown of whiskers on their heads and come in many varieties, including albino and long-finned morphs.
Just be aware that these sucker fish must have waterlogged driftwood in their diet, not just algae. Driftwood also provides an ideal place for algae to grow as well as hiding places for your armored plecos!
- Scientific Name: Ancistrus sp.
- Length: 3 to 5 inches
- Aquarium Size: 20+ gallons
Dwarf Otocinclus are the smallest suckermouth catfish of them all; rarely growing much larger than 1 to 1½ inches! And unlike their larger cousins they are entirely peaceful and even social with one another.
Dwarf Otos make great algae eaters for small tanks and have a tremendous appetite for the green stuff! Just be sure to keep them in groups; a single otocinclus can become stressed if kept singly!
- Scientific Name: Otocinclus vittatus
- Length: 1 ½ inches
- Aquarium Size: 10 gallons
The Clown Pleco is another small sucker fish that is beautiful in its own way, with chocolate brown and light orange stripes! Like the Bristlenose Pleco it also enjoys driftwood to munch on as well as algae and gets no larger than 3 to 4 inches.
Clown Plecos are great sucker fish for smaller tanks since they won’t outgrow them, unlike the larger armored pleco varieties!
- Scientific Name: Panaque maccus
- Length: 3 to 4 inches
- Aquarium Size: 15+ gallons
One fish tank sucker fish that is much rarer but worth the expense is the Zebra Pleco! Also known as the L46 Zebra Pleco, it is an omnivorous pleco, feeding not only on algae but also on crustaceans,worms, and other prey items.
Zebra Plecos need good quality water with high levels of dissolved oxygen and a strong current. They are an intermediate level fish in terms of difficulty. But they can be bred in captivity, assuming you provide them with the right conditions!
- Scientific Name: Hypancistrus zebra
- Length: 3 to 4 inches
- Aquarium Size: 20+ gallons
Setting Up a Sucker Fish Aquarium
From here on out, we will be talking about the Common Plecostomus since it is by far the most common sucker fish to keep! Here is an in-depth breakdown on caring for these South American catfish!
Sucker Fish Aquarium Size
As one of the larger types of sucker fish you will need to plan for an aquarium upgrade in the not too distant future if you only have a 10 or 20 gallon tank. Sucker fish will surpass 12 inches in length; in fact, the Common Pleco is fully mature only once it reaches 18 to 24 inches!
Please think about owning one carefully because they aren’t so easy to get rid of once they get too big. Your local fish store receives several calls per week from folks looking to offload one, as do zoos and public aquariums. And releasing any invasive, non-native fish into the wild is absolutely illegal and will get you into a lot of trouble should you get caught by the Fish and Wildlife Service.
So what if you want a small sucker fish but you aren’t willing to commit to a larger sucker fish aquarium? In that case, study the section on types of suckermouth catfish; several of the species I’ve included are fully grown at much more manageable sizes!
How Long Do Sucker Fish Live?
Sucker fish are fairly long lived fish; anywhere from 8 to 15 years is common for a mature adult. Smaller types of freshwater sucker fish may only live for 3 to 5 years, like the Dwarf Otocinclus.
What Do Sucker Fish Eat?
Nearly all fish tank sucker fish are either herbivorous or omnivorous. In fact, this habit of grazing on algae and plant matter is why they are so often bought by aquarists of all skill levels.
You may not be able to rely on algae alone to feed your sucker fish, however. In a planted aquarium there may be enough thanks to the bright lighting and nutrients from fertilizers. But a fish-only tank may not grow enough – or not have the right type, because not all algae is edible or preferred by them.
Most green algae will be loved to death by your armored pleco, especially green hair algae. Green spot algae is also tasty but harder for a plecostomus to rasp away. Brown algae will not be touched much since it is not a true algae and has little actual nutrition. And red algaes like staghorn or black beard algae are going to be ignored because they tend to be actively poisonous to fish.
If there isn’t enough algae in your tank then you will need to ensure your sucker fish are getting enough to eat. Many end up starving to death because beginners are told they “only eat leftovers” or worse, “sucker fish eat fish poop.”
While they will eat leftover flakes there is rarely enough for these bulky fish. And since they are usually nocturnal, any leftovers are often picked up by the community tank residents as the day progresses.
What do sucker fish eat? Try prepared sinking pellet and wafer formulas that contain spirulina and chlorella algae! These offer precisely the nutrients your plecos need for optimal health. You can also clip lightly boiled vegetables in place near the aquarium bottom, such as lettuce, zucchini, and spinach! The more greens you offer, the better!
Tank Mates for Black Sucker Fish
Choosing tank mates for plecostomus is easy at first: the cute little sucker fish will keep mostly to themselves in the 2 to 3 inch range. But as they get older and larger suckermouth fish tend to become more aggressive and territorial.
Not so aggressive that they will actively cause harm to their tank mates. But they will get pushy if other fish try investigating their favorite hiding places. They will start fighting with each other as well, especially if there aren’t enough hiding places for everyone.
Suckerfish will sometimes also latch onto the sides of large, peaceful tank mates like goldfish, discus, or catfish. They will slurp away some of the nutrient rich mucus from the sides of the fish. Which is stressful for the other fish and invites infections once this barrier is removed from their bare skin.
The best tank mates for sucker fish that are fully grown are equally large and semi-aggressive fish. You often see adult sucker fish being kept as algae eaters in cichlid tanks for this reason. Plus the hard, plate-like scales of armored plecos give them protection in case the cichlid throws a tantrum, as they often will.
Midwater dwelling dither fish are also good choices since they won’t bother the sucker fish in its hideout. These include Silver Dollars and Giant Danios. But you can also keep adult sucker fish with tetras, livebearers, and other very small fish. Even fully grown sucker fish are entirely vegetarian and aren’t interested in eating smaller tank mates!
Keep them away from invertebrates like shrimp or snails, however. Some fish tank sucker fish will ignore a shrimp or snail. But many others find them to be a tasty supplement to their algae diet.
Good Tank Mates for Sucker Fish:
- Cichlids, Gouramis, and other Semi-Aggressive Fish
- Silver Dollars, Giant Danios, and other midwater fish
- Tetras, Livebearers, and other Small Community Fish
Poor Tank Mates for Sucker Fish:
- Goldfish, Discus, Angelfish, and other Large, Peaceful Fish
- Other Sucker Fish
- Snails, Shrimp, and other Invertebrates
Freshwater Sucker Fish Breeding
The majority of black sucker fish in the hobby are actually captive bred; few are caught in the wild these days. Unfortunately, breeding sucker fish is nearly impossible for home aquarists to do.
One main reason is that these fish are impossible to sex visually; the males and females look exactly the same. Even when ready to breed, there are no readily obvious cues; the fish can tell sexes apart from behavioral and hormonal cues that we can’t see.
Another is that sucker fish are cavity spawners that dig mud burrows in nature. They normally begin this process once they receive seasonal cues during the flooding season in their native Amazon. The river starts to swell, revealing new territories that the armored pleco males fight over.
Once a male finds a good spot he then entices a female to enter and lay her eggs. He will then defend them for days as the fry develop within and eventually hatch. The small sucker fish fry are well developed and leave the nest within two to three days of hatching, having fully absorbed their yolk sack and ready to begin munching on algae and biofilm along the bottom of the river!
In Asia sucker fish are raised in huge outdoor ponds where plecos can dig mud burrows and find their mates naturally. Since no home aquarium is large enough for this, you aren’t likely to breed adult sucker fish anytime soon!
Frequently Asked Questions about Sucker Fish
Sucker fish are good community tank residents only when very small. The larger they get the more territorial and pushy they become. So choose semi-aggressive tank mates like cichlids and gouramis to keep alongside one. You can also choose small or large schooling fish so long as they stay in the midwater or upper water column where your sucker fish never swims
Nearly all sucker fish are herbivorous or omnivorous. These types of suckermouth catfish consume algae and bacterial biofilms that form on hard surfaces underwater. Many also eat small amounts of driftwood. Some sucker fish prefer more protein as well, feeding on worms, fish eggs, and even small shrimp or snails, especially Vampire and Zebra Plecos.
This fish has several names, including the Common Pleco, Plecostomus, Black Sucker Fish, Armored Pleco, and Suckermouth Catfish!
The Common Pleco lives to be anywhere from 8 to 15 years in age!