Written by Russell McAndrews
Tanganyikan fishes live in an environment which is spectacularly unique. Similar to a tropical island like Hawaii, very deep water can be found not far from shore. Dead organic matter sinks to depths approaching a mile. These precipitous walls ensure exceptionally clear water and striking and brightly colored fishes. Temperature wise, the lake is almost uniform top to bottom therefore it is isothermic. Few fish live below 100m (300’), the bottom does not contain enough oxygen to support fish-life. The lake water is war, hard, alkaline, and slightly salty. Specific numbers are not critical so long as the theme is adhered to. Rocky or sandy beaches are the prevalent terrain for most of these cichlids available.
Lake Tanganyika has spent somewhere in the neighborhood of 40 million years developing in almost complete isolation. What this means to the fauna of L. Tanganyika is a unique, wondrously diverse, inherently stable, and exceptionally clean habitat. Fauna, is a word which well conveys the extreme diversity to be found, jellyfish and sponges, to cobras and crabs and all in a freshwater lake. What this means to us is that many of these fish do not tolerate dissolved wastes. Many of the most expensive little jams die quite canary-like at the first hint of trouble. Exceptionally susceptible fishes, they’ve even been known to “shock out” while being bagged. In this event wait a while before disposing of the fish as some do come back. Medium to large regular water changes and activated carbon are important to overall success with these fishes. Diet is also very important, all to often, quantities of meaty foods are fed in instances where they should not be. Research any species you have or intend to obtain many of these highly specialized fishes are vegitarian by nature and have correspondingly long intestines. Such digestive equipment is not designed to process any quantity of meat and complications will ensue. Neglect is probably the number one killer of Tanganyikan, they will not tolerate it. Even an unnoticed corpse can cause an ammonia spike capable of filling all. This is the advantage of using activated carbon, it keeps the canaries alive.
Any attempt to lump these fishes together with generalized statements is doomed to failure. All the adjectives listed above and many not mentioned fall short of adequately describing the diverse specialization achieved in this vast lake. Many have debated the question of how many cichlid phylogeny were present at the lake’s formation. Preliminary electrophoretic sampling (enzyme mapping), supports the theory of a pair of cichlid ancestors. Comparatively, L. Malawi is about one third the age of Tanganyika and L. Victoria is less than 750,000 years. In fact, fossil studies give some indication that L. Victoria almost completely dried up only 14,000 years ago. This makes L. Tanganyika and its neighbors individual pages in a text book of evolution. Scientists hope that a detailed comparative analysis of all three lakes will teach us more about the on-going process of evolution than all the information to date. L. Tanganyika gives us a view of what may be in the future for the younger ecosystems. To some degree Tanganyikans can, and for the point of discussion, must be grouped, in this case by reproductive technique.
To breed any of the substrate-spawning cichlids it is important to hatch and feed brine shrimp. Fry will need food immediately after becoming free-swimming but they are so secretive, they are easily overlooked. The way around this is a light daily feeding of newly hatched shrimp, when the fry hatch out there’s food available. With a majority of these species, if you don’t feed live baby brine you will never see the fry. Julidochromis are a good exception to this. A pair in a “live”, established tank will usually produce a few fry at a time which see to find enough to eat to survive in a “dirty” tank.
Different species behave differently some pair bonds seem to be permanent while others are quite fragile. Success in raising fry in a crowded community is another area of great variability. A further point worth mentioning is that Tanganyikan cichlids seem to take longer to mature than others, sometimes as long as 2-3 years.
Mouth-brooding species spawning within the confines of a aquarium typically exhibit rigid pecking orders, meaning that an individual removed even temporarily could be murdered on the reintroduction. The optimum method for reproducing these fish is to take no action until the eggs have hatched (7-10 days post-spawn depending upon species and temperature), net the female, strip her fry from her buccal cavity and return her to the tank immediately. By “strip” I mean hold her, head-down, into a small pail. Using one fingernail, pry her mouth open. The other hand pumps the fills to expel the zygotes. The number of fry being carried is inversely proportional to the carrying time. My interpretation of this is that the longer she carries the fewer fry she can house. Most of these mouth-brooders do not eat their young and can be raised in the tank with their parents provided there are no other predatory species present. Tropheus females have been observed grazing to feed their mouthful of fry and themselves. One of the oddities of the lake is pair bonding between mouth-brooders, although this behavior is found elsewhere, the only instances in East Africa are the Tanganyikan gobies. Male and female apparently share the duties by passing the eggs. Behavior is what makes these fish so fascinating.