Eichhornia (water hyacinth) pencil catfish

Where they come from

Ituglanis eichorniarum is one of those odd little pencil cats from the Amazon that shows up in weedy, tangled margins. The name gives you a hint: they're closely tied to floating plants like water hyacinth, where there are tons of roots, leaf litter, and tiny critters to pick at. Think shallow, warm, tea-stained water with low flow and a lot of hiding spots.

Setting up their tank

These are advanced mostly because they're delicate shippers, picky about microhabitat, and they stress fast in bright, bare tanks. If you set the tank up like a little jungle floor and keep things stable, they settle in and become pretty hardy.

• Tank size: a 20 long works for a small group, but bigger is easier to keep stable (especially if you want other fish with them).
• Substrate: fine sand is my pick. They like to scoot and wedge themselves into places, and sand is gentler than gravel.
• Cover: piles of leaf litter (catappa/oak/beech), root tangles, driftwood, and dense plants. Floating plants help a lot with shade.
• Flow: gentle. Sponge filters or a calm canister return works better than blasting them with current.
• Light: dim to moderate. Bright lights with no shade keeps them pinned and not feeding.
• Water: soft to moderately soft if you can. I kept them best around 24-27C (75-81F) with steady, clean water.

I also like to start them in a mature tank, not a fresh setup. They seem to do better when there is already biofilm, mulm in the leaf litter, and lots of little live foods present (copepods, worms, whatever naturally shows up).

What to feed them

They're not "algae wafer" fish. Mine did best once I treated them like micro-predators that hunt in the clutter. If they are new and stressed, live food gets them eating faster than anything else.

• Live and frozen: blackworms, grindal worms, white worms (sparingly), daphnia, cyclops, baby brine, mosquito larvae where legal/safe, frozen bloodworms as an occasional treat.
• Sinking foods: small sinking pellets for carnivores, micro wafers, and gel foods pressed into the leaf litter so it stays put.
• Target feeding: use a pipette or turkey baster to drop food right into their leaf piles and wood gaps.

Watch body shape more than "did I see it eat." A healthy pencil cat has a gently rounded belly after feeding and doesn't look pinched behind the head. If you only ever see a thin profile, it's time to change tactics (more live food, more targeted feeding, fewer food thieves).

How they behave and who they get along with

They are shy, bottom-oriented, and basically built for threading through roots and leaf litter. Most of the day you'll see a whisker, a tail tip, or nothing at all. At night they come out and do slow, deliberate hunting along the bottom and into plant roots.

• Best kept: in a small group if you can (3-6). They don't school like tetras, but they settle better with their own kind around.
• Good tankmates: small, calm fish that won't hammer the bottom for food - pencilfish, small tetras, hatchetfish, small rasboras (if the temps match), peaceful dwarf cichlids with similar water preferences.
• Avoid: big or boisterous bottom feeders (most Corydoras in a busy tank, large loaches), aggressive cichlids, and anything that will outcompete them at feeding time.

They are more "scared of you" than "aggressive." If you keep their tank dim, give them real cover, and feed thoughtfully, they become a lot less invisible.

Breeding tips

Breeding reports in home aquariums are pretty scarce, so don't feel bad if it never happens. That said, you can stack the odds a bit by giving them seasonal cues and the right kind of hideouts.

• Run them in a species-focused tank or with very peaceful fish. Less stress, more time spent exploring.
• Offer multiple tight spawning spots: small tubes, narrow wood crevices, and leaf piles with a "roof" of wood above them.
• Condition with lots of small live foods for a few weeks.
• Try a "rainy season" routine: slightly cooler water change (not cold), a bit more flow for a day, and heavier feeding before and after.

Common problems to watch for

Most losses with this species happen early: shipping stress, starvation in a community tank, or slow declines from being kept too bright and too exposed.

• Refusing food: usually stress or competition. Dim the tank, add more cover, switch to live foods, and target feed in the same spots each night.
• Wasting away: they are eating less than you think, or worms/parasites are involved. Quarantine helps, and don't be afraid to deworm if you see stringy poop and weight loss despite eating.
• Barbel damage: rough substrate, sharp decor, or chronically dirty bottom. Sand, smooth wood, and regular gentle maintenance helps.
• Getting stuck: they wedge into tiny gaps. Check decor for pinch points and avoid porous rocks with holes that narrow inside.
• Sensitivity to sudden changes: big swings in temperature, pH, or cleanliness hit them harder than tougher catfish.

If you build the tank around their personality (dark, cluttered, calm) and feed like they're hunting in roots, they're a really rewarding oddball. You just have to meet them where they live.