MADAGASCAR RAINBOWFISH
6Scientific name: Bedotia madagascariensis
6Pronunciation: Bay-doh-tee-ah ma-da-ga-ska-ree-en-siss
6Size: To 10cm
6Origin: Endemic to eastern Madagascar
6Habitat: Clear, slow flowing streams with heavy marginal
vegetation
6Tank size: 120x30x30cm
6Water requirements: Soft and acidic to slightly alkaline water;
5.5-7.5pH, 0-12°H
6Temperature: Peaceful community species, sometimes a male
might flare but is unable to cause damage
6Feeding: Wholly unfussy, offer flakes, pellets, live and frozen
Daphnia, bloodworm
6Availability and cost: Not rare, but not exactly common either, so
you may need to shop around. Prices from £5 each
with a large group of two-week old Gold barb, Barbodes semifasciolatus, juveniles.
After a fortnight I spotted a few different looking fry among the barbs. The strangers looked like tiny silver arrows whizzing around the tank at a speed, and as compared to the laid-back barbs they were more slender and more active. I had a closer look with my magnifying glass and to my great surprise I identified them as rainbowfish fry. They must have gotten there as eggs attached to the roots of the Anubias, but it was proof that I had a real pair in the big tank.
I followed the fry development closely taking pictures and notes. The offspring grew quickly, reaching 4cm in less than three months. I managed to raise all four fry. There was a male among the youngsters (red tailed when young but switched to black tail later) and three females.
After they joined their parents, I cleaned out their growing tank, moving some Java moss from there to a shrimp tank. History repeated itself: in two weeks’ time I had four tiny little silver arrows swimming in the shrimp tank. It shows that Madagascar rainbows are sexually mature at a relatively young age, as my fish were barely 5cm long when they spawned.
Interestingly all four of the second batch became males with red tail, despite of their father and grandfather both being black tailed. This leads me to wonder if any future offspring of these males will
show a black tail again. I won’t have to wait long for the answer, as they’re reaching maturity soon.
Happy rainbows
If you want to keep the ‘Poor man’s rainbowfish’, as some people erroneously refer to Bedotia, you have an easy task. They’re undemanding and adaptable, so as long as the basics are covered you will be fine. As they can reach over 10cm when fully grown a long (over 120cm) aquarium is a must.
In the wild they inhabit slow but oxygen-rich streams with very soft water. If you have wild caught fish you should target soft and acidic conditions, but the vast majority of available Madagascar rainbowfish are commercially bred and less demanding. An aquarium filled up with soft to medium hard (0-12°H) and slightly acidic to neutral (5.5-7.5pH) water is perfect for them. The temperature should be somewhere between 22-26°C. They look quite washed out in strong lighting, but if you add some surface vegetation such as Water lettuce, Pistia, your fish will sparkle. Decoration wise you can go with just roots, leaf litter and floating plants, but they would feel equally at home — and look regal — in a densely planted aquarium. Efficient filtration is a must, and even though the perfect torpedo shape typical of riverine fish would suggest otherwise, a strong flow isn’t necessary. Madagascar rainbows are very active swimmers and also talented jumpers, so make sure that the tank is well covered, and while they’re not exactly timid, overly boisterous tankmates should be avoided. Having said that they can hold themselves up quite well even against large fish.
For example, in a suitably large biotope tank they could easily be matched with Paratilapia polleni and used as dither fish.
In my experience, older rainbowfish males can be a bit bullish especially with similarly shaped fish, and my dominant male always flares up when a Torpedo barb, Sahyadria denisonii, passes by. Aside that, they’re peaceful and if you have at least 8-10 of them then you will have a lively community with plenty of interactions. The males will chase the females and the rival males around, but the squabbles are usually harmless and won’t result in any injuries. Feeding them is no issue as they happily gobble up anything edible that falls into the water. Having said that, a varied diet (including live and frozen food beside staple dry goods) using high quality ingredients goes a long way to keeping them in top condition.
Making babies
Well-fed and kept fish will spawn on a regular basis even in community tanks, but the free caviar is usually quickly consumed by the tankmates. In a very densely planted tank with plenty of surface vegetation you may find survivors, but for breeding purposes a separate aquarium should be prepared. My preferred choice is a relatively large and bare tank of at least 60cm long with a large sponge filter. I find the best temperature for breeding to be around 26°C, as it stimulates spawning without jeopardising the oxygen content of the water (warmer water will hold less oxygen than cool).