Your Madagascar Rainbowfish Vet-Prep Sheet
Finfern honest freshwater care · finfern.com Madagascar Rainbowfish — Vet-Prep Sheet
🔍 Find an aquatic / fish vet — before you need one
- Search the WAVMA aquatic-vet finder (the World Aquatic Veterinary Medical Association) — or search "aquatic / fish / exotics vet near me".
- Call ahead and ask the key question: "Do you treat fish?" Few vets do — and ask the exam fee while you're on the phone.
- Find and save one now, while things are calm — not in the middle of a crisis.
📇 Fill this in now — before the crisis
Two minutes now saves ten in a panic. Print it and keep it by the tank.
🚨 Is this an emergency now?
Act promptly — starting with a water test — if you notice any of these:
- Fish gasping at the surface, clamped fins, or suddenly listless: stop feeding and TEST THE WATER right away (ammonia, nitrite, nitrate) - these usually point to a water-quality or cycling problem, not the fish itself.
- Any detectable ammonia or nitrite: do an immediate partial water change and keep testing daily - the tank is not (or no longer) properly cycled.
- Colours washing out and nervous, skittish hiding in an otherwise healthy tank: often a group that's too small or too many males - review shoal size and the male-to-female ratio.
- Persistent chasing that leaves a fish battered, hiding constantly, or unable to feed: add more visual barriers and rebalance toward more females; if it continues, seek help on a reputable fishkeeping forum.
- White spots, cottony patches, ulcers, rapid breathing or unusual swimming: isolate if you can, review water conditions, and seek advice from a vet or an experienced fishkeeping community - this is triage, not a diagnosis.
When in doubt, a vet call is never wrong — most issues are reversible if caught early.
🚗 On the way / while you wait
✅ Do
- Test your water NOW — ammonia, nitrite, nitrate, pH and temperature — and correct the obvious (a big source of trouble is ammonia / nitrite).
- Keep the fish in its own stable, dechlorinated tank water.
- Move it to a hospital / quarantine tank if you already have one set up.
- Keep the tank calm and dimly lit — stress makes almost everything worse.
⛔ Don’t
- Don’t tip in OTC, aquarium-shop or forum “cures” blindly — many are harmful or just mask the real problem.
- Don’t make a big sudden water change or swing the parameters.
- Don’t add salt or medication without knowing the cause.
🎒 What to bring
- A recent water-test result — ammonia, nitrite, nitrate, pH and temperature. Water quality is the root of most fish illness and the first thing a fish vet asks about.
- Clear photos and a short video — it may not show the behaviour or symptom in the clinic.
- A note of your setup and exactly what — and how often — you feed.
- Only if the vet advises transporting the fish: the fish in a bag or tub of its OWN tank water.
🗣️ What to tell the vet
A general vet may not know this species. Come ready to explain its correct care:
- Temperature
- Best kept around 22-26°C (72-79°F). The species is genuinely adaptable - SeriouslyFish quotes a wild range of 23-32°C (73-90°F) and Fishkeeper 23-29°C - but it does NOT need to be kept hot, and steadier, slightly cooler water in the low-to-mid 20s suits it well long-term. It is a heated tropical fish, not a coldwater one; keep it stable.
- pH
- Acidic to neutral, roughly 6.0-7.5. SeriouslyFish gives 4.5-7.5 and Fishkeeper 5.0-7.0. Aim for stable readings in this band rather than chasing an exact number; it adapts to most soft-to-neutral tap water. Avoid hard, high-pH (8+) water.
- Hardness
- Soft to moderately hard: about 2-15 dGH. SeriouslyFish lists 0-15 dGH and Fishkeeper "up to 15 degrees." Very soft, slightly acidic water mirrors its Madagascan stream habitat, but it is not fussy within this range.
- Minimum tank
- Keeper-facing minimum ~110-120 L (about 29-32 US gal) - but the number that actually matters is the LENGTH. SeriouslyFish gives a minimum base of 120 x 30 cm (48 x 12 in), and Fishkeeper.co.uk recommends "at least 4 ft" long. These are fast, restless open-water swimmers, so a long 120 cm / 4 ft tank is the real floor. Bigger-is-better reality: a full shoal of 8-10+ is far happier in 150-200 L+ with a long footprint; extra length beats extra height every time.
- Filtration & flow
- Efficient filtration but GENTLE-to-moderate flow. It comes from slow-flowing, shaded streams, so keep water movement calm - strong current stresses it. Good biological filtration plus regular partial water changes to keep nitrate low is the priority; it is sensitive to poor water quality and to sudden parameter swings.
- Diet
- Omnivore, leaning insectivore. In the wild it feeds mainly on terrestrial insects and other small invertebrates that fall onto the water, so it takes food readily from the surface and mid-water.
- Tankmates / temperament
- Peaceful and non-aggressive toward other species - a genuine community fish. The one nuance is between rival males, which can spar and get a little territorial. This is normal and rarely harmful if you keep females in the majority and provide plenty of plants and visual break-up so no male can dominate open space.
⚕️ Most fish illness starts with water quality, not infection — bring a recent water test; it's the first thing a good fish vet will ask about. Fish medicine is specialised and few vets treat fish, so call ahead. Many aquarium-shop and OTC 'cures' are harmful or simply mask the real problem, so tell the vet exactly what (if anything) you’ve already added, and treat a sick fish in a separate hospital tank rather than dosing the whole display.
Then note which of the warning signs (above) you are seeing, when they started, and whether they are getting worse.
❓ Questions to ask
- Do you treat fish? If not, can you refer me to a vet who does?
- What are the likely causes — and could my water or setup be the cause?
- What is the treatment plan, the likely cost, and what should I watch for at home?
- How do I prevent this from happening again?