The single best upgrade I ever made to my fishkeeping was not a fancy filter or a bigger tank. It was a scraggly bunch of java fern tied to a piece of bogwood with cotton thread. Within a couple of months the tank looked alive rather than decorated, the algae on the glass slowed right down, and my water tests got boring in the best possible way. If you have been putting off live plants because you think they need pressurised CO2, blazing lights and a chemistry degree, I want to talk you out of that idea. A low-tech planted tank is cheap, forgiving, and honestly easier to run than a bare one. ...

Every tank I have ever kept has taught me the same lesson eventually: the water is the pet. The fish are just the visible part of a system that lives or dies on chemistry you cannot see. When something goes wrong in an aquarium, the answer is almost never in the fish themselves. It is in the numbers. The good news is that there are only a handful of numbers that matter, and once you understand what each one is actually telling you, testing stops being a chore and starts being a conversation with your tank. Here is what each parameter means, what a healthy reading looks like, and what to do when a reading is off. ...

Nobody has ever brought me a tank problem that turned out to be underfeeding. Not once. Skinny fish in home aquaria are almost always sick or bullied, not starved. Meanwhile overfeeding sits behind most of the cloudy water, algae outbreaks, snail explosions and mystery ammonia readings I get asked about. Fish are small, cold blooded animals that spend most of the day doing very little. They need far less food than our mammal instincts tell us, and the kindest thing you can do for a tank is to feed it less than feels right. ...

If I could change one thing about how fish shops sell to beginners, it would be the little “starter kits”. The 20 litre cube with a light in the lid, the plastic bowl with a goldfish sticker on the box. They look manageable, they fit on a desk, and they are the single biggest reason new keepers give up in the first three months. I run a room full of tanks now, from 30 litre shell dweller boxes up to a proper community tank, and I will tell you plainly: the small ones are the hard ones. If you are buying your first aquarium, buy bigger than you think you want. Somewhere between 60 and 100 litres is the sweet spot, and here is why. ...

Most aquarium maintenance advice is written for an imaginary keeper with one tank and unlimited enthusiasm. Real life is different: some weeks you have twenty minutes for the fish, some weeks you have two, and any schedule that demands perfection will be abandoned by March. Running several tanks plus outdoor tubs has forced me to figure out what actually needs doing, what can slide, and what should never be done at all. The short version: a tank needs a small amount of genuinely regular work, mostly water changes, and it is harmed by heroic irregular work. Here is the schedule that survives contact with a normal life. ...

If you want to keep a cichlid that behaves like a cichlid, guarding a cave, herding a cloud of fry across the tank, flaring at anything that comes near, without needing a huge tank or fancy water, the kribensis is the classic answer and it still holds up. Pelvicachromis pulcher is a West African dwarf cichlid from the rivers and drainage ditches of southern Nigeria and Cameroon, farmed in vast numbers for the hobby, and forgiving of almost everything a beginner will throw at it. The female’s cherry-red belly, which brightens rather than fades when she is ready to spawn, is one of the best colours available in an easy fish. ...

Ask in a shop for an algae eater and you will usually be pointed at a pleco. The trouble is that “pleco” covers everything from a 10 cm cave-dweller to a half-metre monster, and the cheap ones on the bottom shelf are very often the monster. The bristlenose pleco, sold as Ancistrus sp. or Ancistrus cf. cirrhosus, is the one that actually belongs in an ordinary home aquarium. Mine spend their days rasping the glass and the wood, spawn in caves without being asked, and have never outgrown their welcome. If a suckermouth catfish is going in your tank, make it this one. ...

The betta, Betta splendens, is probably the most mistreated fish in the hobby, and not out of malice. Shops sell them in cups, the internet is full of vase setups, and the myth persists that because wild bettas live in puddles, a jar on a shelf is fine. Wild bettas live in rice paddies, marshes and slow floodplains, which are shallow but enormous, warm all year and full of cover. The puddle story comes from the dry season, when getting trapped in one is the worst thing that can happen to a betta, not its preferred address. I keep bettas on my desk in proper heated, filtered tubs, and the difference between a betta in decent conditions and one in a bowl is the difference between an active, curious, flaring fish and a listless one clamped in a corner. ...

Cherry shrimp were one of the best additions I ever made to my fishroom, and one of the cheapest per animal once the colony got going. Neocaridina davidi, to give them their proper name, are small dwarf shrimp from Taiwan that have been selectively bred into red, orange, yellow, blue and near-black lines. Buy ten, look after them, and within a year you can have hundreds without doing anything clever. In my very hard tap water, around 22 to 23 dGH, they do not merely survive. They moult cleanly, colour up well and breed constantly. If your water is hard and you have been told it limits you, shrimp are one of the animals it actively favours. ...