Can Malawi bloat affect Tropheus too?
I keep seeing references to Malawi bloat in African cichlids. What is this and how can it be avoided? Is it curable and does it only affect mbuna and other Malawi cichlids? I ask because I recently lost my favourite Tropheus and I’d initially thought it was dropsy as the fish was swollen. Now I'm worried it might have been bloat. Any advice would be welcome.
GARETH ROBERTS
JEREMY SAYS: Malawi bloat is a condition that affects mainly the small, colourful mbuna cichlids from Lake Malawi, but it can also affect Tropheus cichlids from Lake Tanganyika.
The natural diet of both algae-grazing mbuna and Tropheus is poor in nutrients, and they spend most of the day scraping aufwuchs, the algae, biofilms, and tiny animals that encrust the rocks underwater. In our aquariums we give them much richer foods, in larger amounts, yet we exercise them less, so mbuna in particular grow larger in captivity, and can become much fatter. In the past, this richer diet, along with the feeding of frozen or live bloodworms was blamed for causing ‘bloat,’ and many African cichlids would fatten up, stiffen up, and succumb to the disease. Twenty years ago, the feeding of these fish with bloodworm was an absolute no-no. Spirulina-based foods and even goldfish foods were fed instead of tropical diets as they were lower in protein, but even then, many Tropheus especially died.
More recently, some observers have begun to think that bloat is actually caused by aggression, when cichlids cannot escape one other in aquaria and sustain internal injuries from being rammed in their sides. Although bloat-affected fish swell up to a degree, it is nothing like the typical pinecone-like swelling caused by dropsy. The latter can also develop in mbuna and Tropheus but is a separate disease.
When I keep either mbuna or Tropheus, I try to mitigate bloat by providing very well-filtered, well-oxygenated water with a high pH and hardness, and I try to keep nitrates below 40ppm at all times—high nitrate levels can actually increase aggression. I also feed goldfish flakes, spirulina flakes and have one ‘starve day’ a week, when I don’t feed the fish, as this encourages them to graze the rocks more.
True bloat may be a bacterial infection, so choose healthy, rested fish from responsible sellers who know about African cichlids, and do all you can to provide excellent water, and a good, low protein diet.