Some fish rush about and demand attention. Altolamprologus does the opposite. These are the still, watchful predators of Lake Tanganyika’s rocky shores, hanging almost motionless in the water with a flat, deep, armour-plated body, waiting for something small and foolish to swim past. I find them one of the most rewarding Rift Lake fish to keep precisely because they are not busy. A well-grown calvus with its pearly spangling, or a stocky compressiceps parked in a crevice, has real presence. And like every Tanganyikan, they are built for exactly the hard, alkaline water that comes out of my tap, which is a large part of why I recommend them to hard-water keepers who want something with more menace than a shell-dweller. ...

If you keep African cichlids for long enough, one day a fish that was fine last week will be sulking in a corner, refusing food, and trailing a length of clear or white stringy waste. That is the start of what most keepers call Malawi bloat, and it is the single problem that has cost me the most fish over the years. It moves faster than you expect, it does not always respond to treatment, and the advice online is a mess of half-truths. The most useful thing I can tell you up front is that bloat is very rarely about your water being too hard. On my tap, which runs about 22 dGH and alkaline, Rift Lake cichlids are exactly where they want to be. What tips them into bloat is almost always what goes in their mouths, and how stressed they are while it happens. ...

Look at most Tanganyikan tanks and you will notice the same thing: all the action is on the floor. Shell-dwellers digging, gobies perched on rocks, cichlids holding territory in the bottom third of the glass, and above them a great empty box of water doing nothing. Cyprichromis leptosoma is the fish that fills it. It is a peaceful, open-water shoaler that spends its whole life drifting and darting in the top two-thirds of the tank, and it is one of the few Rift Lake fish that genuinely wants the space my shell-dwellers ignore. ...

If you have read anything on this site about shell-dwellers, you will have met my multies, a sandy footprint full of little cichlids all shouting at each other over their snail shells. Neolamprologus brevis is the other way to do this. It is still a tiny Tanganyikan that lives in a shell, but it is not a colony fish. A bonded pair takes one patch of sand, settles on a shell, and that is the family. If you want the shell-dweller experience but you have a smaller tank or you simply prefer watching two fish you actually recognise, brevis is the one I point people at. ...

If you want a cichlid with real character, a fish that watches you across the room and rearranges its tank to suit itself, and you happen to have hard alkaline tap water, the convict is one of the easiest recommendations I can make. It is cheap, it is tough, it breeds at the drop of a hat, and it could not care less that your water is liquid rock. The catch, and there is always a catch, is temperament. A breeding pair of convicts is one of the most aggressive things you can put in a home aquarium relative to their size, and going in without a plan for that is how people end up with a tank of shredded fins. ...

Most people with very hard, alkaline tap water spend years fighting it. They buy pH-down, they lug home jugs of RO, they pick soft-water fish and then wonder why the fish never look right. I did all of that before I worked out the obvious thing: somewhere on the planet there is a lake with water almost exactly like the stuff coming out of my kitchen tap, and it is stuffed with some of the most interesting fish in the hobby. That lake is Tanganyika, and building a tank around it is the single easiest fishkeeping I have ever done on my water. ...

If you keep hard, alkaline tap water and you have ever felt short-changed on colour, rainbowfish are the fish I wish more people knew about. Nearly all the bright community fish shops push, the tetras and the rasboras, are soft-water species that never quite settle in my water. Rainbowfish are the opposite. They come from hard, alkaline lakes, so my rock-hard tap is not a compromise for them, it is what they were built for. A mature shoal moving through a well-lit tank, males flashing colour at each other, is one of the best sights in the hobby, and I get it without touching my water chemistry. ...

If you want a shell-dweller but the idea of running a whole colony feels like a lot, the gold ocellatus is the one I point people towards. It is a single fish with an enormous personality, it fits in a tank most people would call too small, and it treats my rock-hard tap water as home rather than something to be corrected. I keep mostly Tanganyikans, and of all of them this is the one that makes visitors laugh out loud, usually because a fish the length of a thumb has just squared up to their finger through the glass. ...

If your tap water is hard, and mine runs about 22.5 dGH, a mystery snail is one of the easiest and most satisfying things you can add to a tank. Most livestock in this hobby wants softer water than my tap gives; the mystery snail is the happy exception, because a shell is made of calcium carbonate and my water is dripping with the calcium to build one. I have kept these big, unbothered snails alongside my livebearers for years, and other than remembering to feed them properly they ask for almost nothing. This is a snail you actively want, not one you fight to get rid of, and that distinction is the whole point. ...

If you have hard, alkaline tap water and you fancy a cichlid with real colour, the electric yellow is the one I steer people towards first. Labidochromis caeruleus is a Lake Malawi mbuna, which normally means aggression and a species tank full of scraps, but the yellow lab is the gentlest of that rowdy family and it takes to my rock-hard tap without a single additive. I keep mostly Tanganyikans, so this is the Malawi fish that snuck into my heart: a banana-yellow body with jet-black fin edges, out in the open all day, and none of the sulking you get from soft-water fish stuck in the wrong water. There is a catch or two, mostly around feeding, and I will be straight about those. ...