Tequila splitfin

Where they come from

Tequila splitfins are a little slice of fishkeeping history. They come from the Teuchitlan River system in Jalisco, Mexico (near the town of Tequila), and in the wild they got hammered by habitat changes and introduced fish. A lot of the ones in the hobby trace back to conservation breeding lines, which is pretty cool and also a good reason to keep them thoughtfully.

Setting up their tank

Think of them like tougher livebearers that still appreciate clean, stable water. I have had the best luck giving them some swimming room and lots of cover so the females can take a break from attention.

• Tank size: 20 gallons long works nicely for a small group. Bigger is always easier if you want more males or you plan to breed.
• Filtration: moderate flow and plenty of biofiltration. A sponge filter plus a hang-on-back is a nice combo if you are raising fry.
• Temperature: they do great in the low 70s F (around 22-24 C). They do not need hot water like some tropical livebearers.
• Hardness/pH: they generally like harder, more alkaline water. If your tap is on the soft/acidic side, go slow and focus on stability rather than chasing numbers.
• Decor: dense plants (guppy grass, hornwort, java moss), rock piles, and wood all work. Give them line-of-sight breaks.
• Substrate: anything is fine. Dark substrate makes their colors pop, especially the males.

They are active and curious, so tight lids matter. They are not notorious jumpers like some killifish, but I have still found the occasional surprise carpet fish when a gap was left open.

What to feed them

These guys eat like livebearers with an extra interest in meaty foods. If you keep them on flakes only, they will live, but they color up and breed better with variety.

• Staples: good quality flake or small pellet (I like a mix of a spirulina-based food and a higher-protein community pellet).
• Frozen/live: daphnia, baby brine shrimp, cyclops, mysis, and bloodworms as a treat.
• Greens: blanched spinach or zucchini now and then, or algae wafers that they can pick at.
• For fry: baby brine shrimp is the fast lane. Microworms and finely crushed flake also work.

How they behave and who they get along with

Tequila splitfins are lively and a bit pushy, especially the males. They are not mean in the cichlid sense, but they can be relentless with chasing and displaying. In a cramped tank, that turns into stress fast.

• Best group setup: more females than males. I aim for 1 male to 2-3 females if I want peace.
• Temperament: active, always exploring, males spar and posture a lot.
• Good tankmates: other robust, similar-temperature fish that will not get bullied or outcompeted. Think tougher livebearers, many rainbowfish, or medium tetras in the right setup.
• Tankmates to avoid: slow long-finned fish (they can get nipped), tiny nano fish, and anything that needs very warm, soft, acidic water.

Breeding tips

They are livebearers, so breeding is more about managing the adults than getting them to spawn. Once the group is settled and well fed, you will start seeing fry show up pretty regularly.

• Pregnancy and fry: females carry for several weeks and drop small batches. It can feel like you get a few fry at a time rather than one huge guppy-style dump.
• Fry survival: adults will eat fry if they can find them. Heavy plants and floating cover make a massive difference.
• Breeding setup: a separate grow-out tank is easiest. Move pregnant females only if you can do it gently and without stressing them.
• Raising fry: feed tiny foods 2-3 times a day and keep the water clean with small, frequent water changes.

Common problems to watch for

Most issues I have seen with splitfins come from crowding, warm stagnant water, or not enough structure in the tank. They are hardy, but they do not like being stressed all the time.

• Chasing stress: constant harassment leads to clamped fins, hiding, and skinny females. Fix with more space, more cover, and fewer males.
• Fin nipping: usually shows up in under-decorated tanks or mixed with tempting long-finned species.
• Bloat/constipation: often from overfeeding rich foods. Add more fiber, feed smaller portions, and skip a day if needed.
• Ich and other parasite flare-ups: often after new fish or big temperature swings. Quarantine new arrivals if you can.
• Water quality crashes: heavy feeding for fry can foul water fast. Watch ammonia/nitrite and do frequent small water changes.