Riggenbach's ctenopoma

Where they come from

Riggenbach's ctenopoma (Ctenopoma riggenbachi) is one of those Central African oddballs that feels like it wandered out of a swampy forest pool and into your fish room. They're from the Congo basin region, where the water is often warm, tannin-stained, and full of leaf litter and roots. That background explains a lot about how they act in a tank: slow, sneaky, and happiest when they can melt into cover.

Setting up their tank

Give this fish space and structure, not a bright, wide-open box. They are ambush hunters and stress easily if they feel exposed. A tank with lots of visual breaks (wood, plants, tall decor) makes them come out more, not less.

• Tank size: I would not keep an adult in anything under 40 gallons, and 55+ is more comfortable if you want tankmates.
• Layout: driftwood tangles, rock piles (stable), and dense planting or tough plants (Anubias, Java fern) attached to wood/rock.
• Lighting: dim to moderate. Floating plants help a ton.
• Substrate: whatever you like, but darker substrates make them bolder.
• Flow: gentle. They do not love being blasted around, and they like to hover and stalk.
• Cover: a tight lid. These fish can jump, especially when spooked.

Water-wise, they are not as fragile as people make them out to be, but they punish sloppy maintenance. Keep ammonia and nitrite at zero, keep nitrate low, and do steady water changes. They do fine in soft to moderately hard freshwater as long as you are consistent. Sudden swings (big pH changes, big temp drops) are what set them back.

What to feed them

They are predators. They will learn pellets sometimes, but most of the time you will get the best growth and behavior from meaty foods. Think of them like a patient hunter, not a frantic eater like barbs.

• Staples I have the best luck with: frozen krill, chopped shrimp, mysis, high-quality carnivore frozen blends.
• Good additions: earthworms (rinsed), blackworms, live or frozen bloodworms (as a treat, not the only food).
• Pellets: some individuals take sinking carnivore pellets after a while. Start by mixing pellets into a "cloud" of frozen food so they accidentally sample them.

They can be surprisingly greedy once settled, but they still eat like a ctenopoma: slow, deliberate, and usually after lights dim. Feed smaller portions more thoughtfully rather than dumping a pile in. Watch the belly line - you want a gentle fullness, not a stuffed sausage look.

How they behave and who they get along with

This is an advanced fish mostly because of temperament and mouth size. They are not constantly aggressive, but they are opportunists. If another fish can fit in that mouth, it will be tested sooner or later, usually at night.

• Best tankmates: sturdy, medium-to-large fish that are not tiny snack-sized - Congo tetras (adult size), larger barbs, robust rainbowfish, bigger Corydoras species, Synodontis catfish.
• Tankmates to avoid: small tetras, guppies, juvenile anything, tiny bottom fish, slow fancy fins they might nip, and anything that sleeps on the substrate looking like a snack.
• With other ctenopomas: possible in a big tank with lots of cover, but expect posturing and occasional scuffles. Add them together, not one-by-one.

They can also be a little "spooky" for the first few weeks. Mine always did better once they had a few predictable routines: same feeding spot, same time, and lots of shaded hiding places. After that, they start perching out in the open and watching you, which is half the fun.

Breeding tips

Breeding Ctenopoma riggenbachi in a typical community setup is uncommon. They do not breed as casually as some gouramis, and you usually need a dedicated tank and a compatible pair. If you are serious, think of it as a project fish, not a happy accident.

• Set up a species tank with heavy cover and floating plants. Calm, dim lighting helps.
• Condition them hard with varied meaty foods for a few weeks.
• Warm, clean water and frequent smaller water changes often trigger spawning behavior in labyrinth fish.
• If they do spawn, the eggs and fry are vulnerable. Plan on separating adults or raising fry in a separate setup.

Common problems to watch for

Most issues I have seen come from three things: stress from being too exposed, poor food choices, and introducing disease with live foods or new fish. They are hardy once settled, but they sulk and get sick fast if you keep them on edge.

• Refusing food: usually stress or too much light. Add cover, dim the tank, and offer smelly frozen foods like krill or shrimp.
• Skin/fin issues after new additions: quarantine your new fish. Ctenopomas do not love being hit with parasites while they are still settling in.
• Bloat/constipation: too many dry pellets or fatty foods. Rotate foods, use smaller meals, and add occasional rougher items like chopped earthworms.
• Mouth injuries: can happen from slamming the lid during a jump or from fighting. Keep the lid secure and avoid cramped setups.
• Hiding nonstop: often a tank layout problem. They want places to perch and peek out, not just one cave.