Dragon fin tetra

Where they come from

Dragon fin tetras (Diapoma terofali) come from South America, in smaller river systems and calmer side waters where the current is not blasting all day. Think tannin-stained water, leaf litter, roots, and lots of broken line-of-sight. That background explains a lot about why they act jumpy in bright, bare tanks and why they color up best in a more "natural" setup.

Setting up their tank

Give them space to school and a few safe zones to duck into. I have had the best luck with a 20 long or larger for a group, mostly because they use the horizontal space and they spook less when they can spread out.

• Tank size: 20 long minimum for a group, bigger is noticeably easier
• Group size: 8-12 is where they start acting confident
• Substrate: dark sand or fine gravel (they look better and act calmer)
• Hardscape: driftwood, rooty branches, leaf litter, and a few rock piles if you like
• Plants: stems around the edges plus floating plants to dim the light

Filtration-wise, they do not need rapids. Moderate flow with good oxygen works great. I run a sponge filter or a gentle hang-on-back with a prefilter sponge so the intake is not a fish vacuum. If you can, keep the lighting a bit subdued. Floating plants (salvinia, frogbit) do more for their confidence than most people expect.

Water numbers do not have to be exotic, but they respond well to cleaner, softer, slightly acidic water. Stable matters more than chasing a specific pH. If your tap is hard, they can still be kept, just watch stress and fin condition and keep up with water changes.

• Temperature: 74-79 F (23-26 C)
• pH: roughly 6.0-7.2 is a comfortable range
• Hardness: soft to medium is easiest
• Maintenance: weekly water changes keep their fins and color looking sharp

What to feed them

These are not picky once settled, but they do best with variety. Mine always colored up and filled out better with some meaty foods mixed in, not just flakes. They have small mouths, so think small particles.

• Staples: quality micro pellets, small flakes, or granules
• Frozen: daphnia, cyclops, baby brine shrimp, chopped bloodworms (sparingly)
• Live (if you can): baby brine shrimp, grindal worms, daphnia

How they behave and who they get along with

In a decent-sized group they are active, alert, and pretty fun to watch. They do a lot of quick darts and little display postures, especially the more colorful fish, but it usually stays at "arguing" level. If you keep too few, they get skittish and sometimes pick at each other more.

• Temperament: generally peaceful, with mild sparring
• Best vibe: larger groups, dimmer light, lots of visual cover
• Top-level behavior: they hang midwater and use open lanes to cruise

Tankmates should be calm community fish that like similar water. Avoid big finny slowpokes that invite nipping, and avoid hyper-aggressive species that keep them pinned in corners. I like them with other small tetras, pencilfish, Corydoras, small plecos, and peaceful dwarf cichlids that are not spawn-crazy.

Breeding tips

Breeding is doable, but it is not the automatic "oops, babies" tetra. They scatter eggs and will snack on them if given the chance. If you want to try, set up a simple breeding tank and make it easy to collect eggs away from the adults.

• Breeding tank: 10-20 gallons, bare bottom or very dark substrate
• Spawning media: fine-leaf plants, spawning mop, or a mesh/egg crate bottom so eggs fall out of reach
• Water: a bit softer and slightly acidic helps, kept very clean
• Conditioning: feed frozen/live foods for 1-2 weeks

I have had the most luck pairing off a well-fed group, then moving a conditioned male and female (or a trio) into the breeding tank in the evening. Keep it dim. If they spawn, pull the adults the next morning. Fry food is the usual tiny-stuff routine: infusoria or powdered fry food first, then baby brine shrimp once they can take it.

Common problems to watch for

Most issues I see with this fish come from stress. Stress makes them pale, twitchy, and more likely to get sick. Start with the basics: stable temperature, clean water, and a group size that lets them relax.

• Jumping: usually from sudden light changes, chasing, or feeling exposed
• Pale color and hiding: too bright, too few fish, no cover, or aggressive tankmates
• Fin fraying: nipping in small groups, or rough decor, or water quality sliding
• Ich and other "new fish" parasites: common if they are shipped/held badly
• Bloat/constipation: too many dry foods without variety

If you get a new batch and they are acting fragile, I treat the first two weeks like a settling-in period: calm tank, steady schedule, small feedings, and no big changes. Once they start swimming out front at feeding time, you are basically past the hard part.