Guatemalan headstander

Where they come from

Guatemalan headstanders (Roeboides guatemalensis) are Central American characins from river systems around Guatemala and nearby regions. Think warm, moving water with lots of structure - rocks, roots, and edge cover - and a steady supply of smaller fish to pick on.

Setting up their tank

Give them a long tank with current. Mine were night-and-day better in a 4 foot footprint than in a taller tank with the same gallons. They like to cruise and posture, and the extra run reduces nonstop chasing.

• Tank size: I would not keep a group in less than a 75 gallon. Bigger is easier with these.
• Filtration: strong canister or sump-style turnover, plus a powerhead to create a clear flow direction.
• Flow: moderate to strong. They sit at angles and play in the current, and it keeps them active.
• Scape: open swimming lanes with breaks of wood/rock. They use cover to break line-of-sight, which cuts aggression.
• Substrate: sand or smooth gravel. Theyre fast and can scrape themselves on sharp stuff.
• Lighting: not picky, but floating plants or shaded zones help them feel less exposed.

Water-wise, aim for clean and stable more than chasing a magic number. Warm tropical freshwater suits them. I kept mine in the mid-70s to low-80s F without drama, as long as ammonia and nitrite stayed at zero and nitrates stayed reasonable.

What to feed them

Theyre not algae headstanders. Roeboides are meat-eaters that do best with a high-protein diet and variety. If you only feed flakes, they stay skinny and way too interested in tankmates.

• Staples: quality carnivore pellets and sticks sized for their mouth (they strike hard, so sinking is fine).
• Frozen: mysis, krill, chopped shrimp, bloodworms (as a treat), and good mixed predator blends.
• Fresh: chopped prawn or fish fillet occasionally (small portions, rinse well).
• Live: guppies or feeder fish are a bad habit in my experience (disease risk and it trains them to hunt everything). If you do live foods, use live blackworms or cultured foods you trust.

How they behave and who they get along with

Theyre called headstanders for a reason - youll see them angle down and hold odd positions, especially in current or when sizing each other up. They are active, alert, and not shy once settled.

The big thing: they can be fin nippers and scale eaters. Some individuals are worse than others, but you have to plan like youll get the spicy one.

• Best kept: in a group (6+) if the tank is large. A small group in a small tank turns into constant bullying.
• Good tankmates: robust, quick fish that dont have long fins and arent bite-sized. Think larger barbs, tough cichlids that arent slow, and some medium-large catfish.
• Risky tankmates: angelfish, discus, gouramis, slow fancy fish, long-finned anything, and most peaceful tetras.
• Will be eaten: tiny fish and thin-bodied juveniles that fit in their mouth.

Aggression management is basically: space, current, and line-of-sight breaks. If you can set up two main territories with a big piece of wood or rockwork in between, you will see less nonstop sparring.

Breeding tips

Breeding Roeboides in home aquariums is not something most hobbyists pull off, and I never had a reliable spawn. Theyre not like common tetras that casually scatter eggs in a planted tank and surprise you.

If you want to try anyway, the closest route is a dedicated breeding setup with a conditioned group, heavy feeding, and a seasonal cue approach (big cool-water changes followed by warmer, heavier feeding). Youd also want a way to separate adults from eggs immediately because they wont babysit.

Common problems to watch for

• Fin damage and missing scales on tankmates: usually aggression or hunger. Fix stocking, space, and feeding before you reach for meds.
• Mouth injuries: they hit food hard and spar. Watch for split lips or fuzzy patches that turn into infections.
• Ich and stress outbreaks after new additions: they dont love sudden changes. Quarantine new fish and keep the tank stable.
• Skin scrapes from chasing: sharp decor and rough gravel make this worse. Smooth surfaces help a lot.
• Bloat/constipation: too many dry foods without variety. Mix in frozen and dont overfeed.

If you keep the water clean, give them room, and feed them like the predators they are, theyre fascinating fish. Just go in with eyes open: theyre an expert-level personality, not a community fish centerpiece.