Yeah some of the tangies fall into the same category too, it depends on the depth of the part of lake they come from as to how viable algae eating as a lifestyle is, but in all the rifts lakes, malawi, tanganyika, and victoria there are species that mirror each other and exploit similar niches , its a fine example of convergent evolution. In all the great lakes there are benthic, pelagic and shallows dwelling species. Generally its the shallows dwelling algal browsers you have to watch for "malawi" bloat from excess protien and dietary fat. Thats why for them youd perhaps choose a food like cichlid excel rather than the regular formulas, spiriluna sheets, bits of blanched veg, and still include some livefood and protien, but keep it a fairly small proportion of the diet, and give them weeks free of livefoods to let the livers clear, and more realistically represent an opportunistic lifestyle.
I mean, sure, although chronomid midge larvae may bloom in their billions, even trillions, and fish produces eggs and fry in millions, there are ebbs and flow in the supply, the midge breed yearly, crustaceans and shrimp much the same, molluscs have maturation rates, everything has a peak time, precisely with the intention to exceed the intake of the the predational species. While a rift cichlids might include, " his , or this " they wont be getting them all the time, the algae will be the only constant in the african sunshine, as will the micro-organisms that live on it, and all the other foods have seasons, or migratory stages limiting their availability for much of the year. The great lakes are deep, baby fish and midge larvae migrate to the depths taking them out of the way of predators who do not always have the ability to adjust to pressure, and of course the size of the lakes is vast, some are the size of a small country, and the cichlids are territorial ie rooted to the spot, most arent pelagic and wont chase shoals of food, so they stay put and take what time and the developmental stages of life brings them, so its not normal to get livefoods every day for these small territory holders.
More predatory and more generalist fish tend to be of a bit less concern when it comes to the diet. Predators given too much veg tend to point blank refuse it and wait for animal protien, but something like the algal browsers from the great lakes might pig out on protien and animal fats and kill itself. In the game of life they take every oportunity, few as they are, in captivity they have no self limiting behaviour and will pig out on foods that are too rich for them.
Its a bit like goldies- they dont come from a hot country, the winters are cold, they cant feed then, hence they eat all spring and summer, and when the cold comes, the richer foods disappear, and they slow down, they diet off, something an indoor goldfish aquarium doesnt represent - hence your average goldie is quite happy to eat itself to death. Anything with a strong opportunist streak tend to be able to over-eat quite badly, and many hybrids seem to do it irrelevant of the evolution of their ancestors.
Not that any of the above excuses people for starving fish, what they are doing is treating a fish like a cat, taking a look at a tin of whiskers and giving it 2 or 3 three gram chunks instead of the half tin it really needs. Underfeeding enough to dwarf a fish really needs the keeper to be insanely off base on amounts, TBH most keepers overfeed, but the shops, well.... call me cynical but lets face it- its about cost cutting, and keeping the fish looking a bit "baby" , basically trying to keep them attractive for sale. Not good.
An aquarium size and a stocking level and filtration level should be defined not only from the standpoint of water quality, territory, humane habitable space, swimming room for fitness, oxygen saturation, and the bioload of the fish including the impact of its normal feeding, but its also very important not to get skewed and start to prioritize one factor over another.
Monocirrhus polyacanthus (african leaf fish).Its a fish that a suprising percentage of owners manage to kill, though its not at all clear to them why. In housing it the factors to consider are thus.
1) Not a big swimmer, its an ambush predator, stays still a long time, primary interest in life- sitting waiting for prey to come past. So you think what- 10 gal or less? Crappy little minimal sponge filter?
2) It doesnt need a lot of surface area for breathing, it has a mostly anaerobic metabolism. So a small surface area is ok, right?
well, you'd be wrong because this fish differs from most, its metabolism despite the lack of movement is actually quite fast, and its digestion very inefficient, its an obligate piscivore and has to have fish, it may well never accept any other kind of food. It has to eat the equivalent of 2-3 guppies or small tetras a day to every other day or die. This of course means it craps a lot and respires a lot of waste products. The equivalent of 2-3 small fish decomposing in your tank every day give or take.
To feed it correctly you have to give it water volume to take up the slack in the water perameters and take this fish to a level of stability it will do well on, actually meaning it really needs for those water perams to be stable and its life worth living, and obviously a filter with some proper biomedia and some space for bacterial growth and flexibility in colony size is better than a cheapy sponge filter.
Therefore we have a small fish that you'd assume could be kept in tiny aquaria, quite naturally in real terms needing almost twice the size youd imagine, and a filter damn near twice the size too, taking you into overfiltering. So a fish's diet can actually dictate its proper aquarium size.Whatever the factors in a fishs life dictate tanksize, you always have to roll with the one that gives the largest size.
Blows inch of fish per gallon, or fish per inches of aquarim estimates all to hell doesnt it?
Much the same can be said of many eartheaters and detritivore catfish too. Their aquarium needs for volume may exceed their personal physical dimensions and need for movement purely because you need a water volume and filtration level able to handle decomposition levels most keepers wouldnt want in their aquarium for their normal feeding style, and again it can be a similar ballgame when encouraging aufwuchs and infusoria for tiny fry, so the best fry are often raised in larger aquaria rather than in small breeder-esqe factory accommodation.
Indeed with some fish all thats necessary to breed the fry is to remove the adults from a larger aquarium, ive raised many rainbowfish that way, I dont even have to feed them for two weeks- the in tank cultures handle the firstfoods! Im sure im not alone in having moved fish from one aquarium to another, left one empty, not bothered to turn it off and strip it dowwn - and behold - fry, and fry doing very well too!
The point of all this going off tangent is of course to point out how ridiculous it is to worry about how much you feed tyour fish if you think your tank cant cope. Youve got to ask yourself why you didnt equip better, and if you wish to keep the fish, to go bigger and better equipped is a complete and inescapable obligation. By complicity of course, thats how unacceptable underfeeding in shops is, and indeed we have many fshops to thank not only for the diseases that are spread, but the fact that the fish are more vulnerable to such diseases because basically they are starving the fish at one of the most crucial developmental stages in their lives, and basically ruining the fish for the new keeper.All because they want overstock displays, and want to cut costs.
Have a think back , and see how many of you might have been stung by this extremely common practise at one point or another? How many of you have had disease outbreaks of basic bacteria and fungi that a fish with a healthy metabolism really shouldnt suffer from I wonder? How many of you have bought a betta that dies in a very short time, perhaps because you had no way of knowing how old it it? How many misconceptions of fish behaviour written on cichlid forums are to do with fish that have never and will never reach full sexual maturity?
I bet every single one of you has been hit by the consequences of underfeeding in shops at one time or another.