Tumba tetra

Where they come from

Tumba tetras (Alestopetersius tumbensis) are Congo basin fish from Central Africa. Think slower river edges, backwaters, and places with plants, roots, and leaf litter. They are not a blackwater-only fish, but they definitely look and act more relaxed in that kind of "riverbank" setup than in a bright, bare tank.

Setting up their tank

Give them room to move. These are active, midwater swimmers, and they look best when you keep a real group and let them cruise. I would not bother with them in a tiny tank even if the math says you can.

• Tank size: 30 gallons minimum for a group, bigger is nicer if you want them to really color up and school
• Group size: 8-12+ (small groups get nippy and shy)
• Temperature: 74-80F (I keep mine around 76-78F)
• pH: roughly 6.0-7.5 (stable matters more than chasing a number)
• Hardness: soft to moderately hard is fine as long as it is consistent
• Filtration: decent flow and lots of oxygen, but not a blasting river-tank current

Decor wise, go for plants (real or fake), wood, and some shaded areas. They will use open space, but they like having a "safe edge" to retreat to. A darker substrate and a bit of tannin tint (leaf litter or botanicals) makes them bolder and cuts down on fin-nipping.

What to feed them

They are classic tetras in the sense that they will eat just about anything that fits. The difference is they have a good appetite and can get a little competitive at mealtime, so spread food out or feed in two spots.

• Daily staple: a quality flake or small pellet (I like a mix so they do not get stuck on one texture)
• Frozen: bloodworms, daphnia, brine shrimp, cyclops
• Live (if you do it): small daphnia or baby brine shrimp is great conditioning food
• Plant matter: they do not need algae wafers, but a spirulina flake now and then does not hurt

How they behave and who they get along with

In a proper group, they are busy, alert, and fun to watch. In a too-small group, they tend to redirect that energy into chasing and fin-testing. You will see it most on slow, flowy-finned tankmates.

They are generally peaceful with other medium community fish that can handle some activity around them. I treat them like a slightly spicier tetra rather than a totally mellow one.

• Good tankmates: Congo tetras, other African tetras, rainbowfish, barbs that are not notorious fin-nippers, Corydoras, Synodontis (smaller, peaceful species), bristlenose plecos
• Use caution with: angelfish, fancy guppies, long-finned gouramis, bettas (they may pester fins)
• Avoid: very timid nano fish that get outcompeted, or aggressive cichlids that will stress them nonstop

Breeding tips

They are egg scatterers, and like a lot of African tetras, breeding is doable but not as "accidental" as some common South American species. Adults will eat eggs if they find them, so you need a plan.

• Use a separate breeding tank if you are serious (10-20 gallons works)
• Add a spawning mop or a thick mat of fine plants (java moss works) so eggs drop out of reach
• Condition the group with frozen/live foods for 1-2 weeks
• Slightly cooler water change can trigger spawning in my experience
• Remove adults after you see spawning activity or once you spot eggs

Eggs usually hatch fast (often within a day or two depending on temperature). Keep the light low. First foods are the usual tiny stuff: infusoria or powdered fry food at first, then baby brine shrimp once they can take it.

Common problems to watch for

Most issues I see with these come from stress stacking: small group, bright tank, not enough cover, and inconsistent water. Fix the environment and they stop acting "touchy".

• Fin nipping: usually from too few fish in the group or not enough space/cover
• Ich after a new addition: they can be a bit sensitive to sudden temperature swings, so quarantine and keep temps steady
• Wasting/skinny fish: often internal parasites from wild-caught or poorly sourced stock - quarantine and watch body condition
• Jumping: they will launch when spooked, especially in new tanks or during chasing