Tropical Fishkeeping for Beginners

Tropical fish are one of the most rewarding pets you can keep at home — no walks, no litter trays, and a tank that becomes genuinely calming to sit and watch after a long day. They're also more accessible than a lot of people assume. You don't need a huge amount of space, a big budget, or years of experience to get started — you just need to get the first few steps right, which is exactly what this guide is for.

If you'd rather talk it through in person, pop into the shop any time — our team is always happy to chat through what would suit your space and answer any questions before you buy anything.

Most beginners start with a starter kit, and that's a completely sensible way in — a good kit will already include a filter, heater and light sized correctly for the tank, so you're not trying to match up separate components on your first attempt.

Here's the thing most people get wrong, though: bigger tanks are actually easier, not harder. It feels counterintuitive to recommend a larger tank to someone who's never kept fish before, but a larger volume of water is more stable — it resists sudden swings in temperature and water quality far better than a small one. A tiny tank punishes small mistakes quickly; a larger one gives you room to learn. As a rough guide, aim for something in the 60–100 litre range if you have the space for it, rather than the smallest starter tanks on the market.

Wherever you land, think about where it'll live before you buy: away from direct sunlight (which drives algae growth), away from radiators and draughts, and on a stand or cabinet rated to take the weight once it's full of water.

If you're keen to go beyond a starter kit and choose your own filter, heater or lighting separately, we've got dedicated guides for that — see Where to go next below.

This is the step that trips up more new fishkeepers than anything else. Before your tank can safely hold fish, it needs to build up a colony of beneficial bacteria that breaks down fish waste — this is called "cycling," and it's what stops ammonia and nitrite building up to dangerous levels.

The traditional advice is to cycle the tank with no fish in it at all ("fishless cycling"), which is genuinely the safest route and worth doing if you're happy to wait a few weeks before adding anything. But it's not the only responsible option. With the right products — a good dechlorinator and a live bacteria culture — and by testing your water regularly, fish-in cycling can also be done safely, adding a small number of carefully selected fish early on and monitoring closely as the tank matures. If you go this route, frequent water testing isn't optional — it's how you catch a problem before it becomes one, which is exactly why our free guide includes a testing record sheet. Testing is only half the job, though: be ready to carry out a water change whenever it's needed rather than on a fixed schedule — if ammonia or nitrite show up, a change is essential straightaway, and it may need to be a significant one rather than a token top-up (see Water testing and ongoing maintenance below).

This is not a process to rush. Whichever approach you choose, expect cycling to take several weeks, and treat patience as the single most important skill of the whole process — resist the urge to add lots of fish at once just because the tank looks ready.

Once your tank is cycled (or well on its way, if you're fish-in cycling), it's time to think about stocking. The single biggest factor in how easy a fish is to keep isn't really the species itself — it's how well that species suits the tap water you're starting with. Matching your fish to your water parameters, rather than picking whatever looks best in the shop, makes the biggest difference for a beginner.

As a rough guide: mollies, platies and guppies do best in harder water with a slightly higher pH, while tetras generally prefer softer water with a lower pH. Bring in a sample of your tap water, or ask us to test it, and we can help you work out which group is the better match before you buy.

One more thing worth knowing: platies, mollies and guppies are all live-bearing fish, meaning they give birth to free-swimming young rather than laying eggs. Keep males and females together and you can end up with a large number of fry fairly quickly — worth deciding upfront whether that's something you want to manage, or whether you'd rather keep just one sex, or a species that doesn't breed as readily.

Add fish gradually — a few at a time, with a week or two in between — rather than stocking the whole tank on day one. This gives your filter's bacteria colony time to keep up with the extra waste each new fish adds.

Overfeeding is probably the single biggest cause of problems in a new tank, and beginners are highly likely to do it without realising — so we deliberately keep our feeding advice simple. We never recommend feeding more than once a day while you're starting out, and we'd actually suggest going a step further: feed every other day rather than daily. A good quality granular food (rather than flake) is a better choice for beginners too, as it's easier to dose accurately and less likely to cloud the water if a little goes uneaten. Between the granular food and the every-other-day routine, it's much harder to accidentally overfeed — which is exactly the point.

Testing your water regularly — especially in the first couple of months — is the single best habit you can build as a new fishkeeper. You're checking for ammonia, nitrite, nitrate and pH, and it's the quickest way to catch an issue while it's still easy to fix.

As a normal routine, we generally recommend a small water change every week, or a larger one every two weeks if that fits your schedule better, with filter media cleaning done separately — usually about once a month. But treat that schedule as a default, not a rule: if a test ever shows any presence of ammonia or nitrite, a water change is essential regardless of when your last one was, and it may need to be substantial — anywhere up to 70%, not just the usual small top-up — to bring levels back down quickly. Testing and water changes work together here, not on separate timetables.

This is exactly the routine our free guide is built around — it comes with a printable record sheet so you can log your results over time and actually see your tank stabilising, plus a fish tracker so you've got a record of what's in there and when it went in.

A few things worth avoiding: adding all your fish on the same day, rushing the cycling process instead of giving it the weeks it actually needs, skipping water testing because everything "looks fine," choosing a tank that's too small because it seems more manageable, and forgetting to dechlorinate tap water before it goes anywhere near your fish. Every one of these is easy to avoid once you know to look out for it — which is really what this whole guide is about.

It depends more on your tap water than the species itself — the easiest fish for you are the ones suited to your water parameters. Mollies, platies and guppies tend to do well in harder, slightly higher pH water, while tetras generally prefer it softer and lower pH. Bring in a water sample and we can help you match it up.

Somewhere in the 60–100 litre range is ideal. It's more forgiving than a very small tank, without being unmanageable for a first-timer.

Yes — your tank needs a colony of beneficial bacteria to process fish waste safely. This can be done with no fish present (fishless cycling) or, with the right products — including a live bacteria culture — and regular testing, gradually with a small number of carefully selected fish. Either way, it's a process worth being patient with rather than rushing.

Weekly is fine once everything's settled and stable. Right at the beginning, though, test more frequently than that — it lets you catch any rise in ammonia or nitrite really quickly, and just as importantly, confirm that the water changes you're doing are actually bringing parameters back to safe levels.

Yes — a good starter kit gives you a correctly matched filter, heater and light in one go, which is a sensible way to begin.

This guide covers the essentials, but there's plenty more to explore once you're settled in:

• Easy Aquarium Plants — coming soon
• Beginner's Guide to Planting a Tank — coming soon
• Choosing the Right Filter for Your Tank — suggested addition
• Choosing an Aquarium Heater — suggested addition
• Choosing Aquarium Lighting — suggested addition

And of course, if you'd rather talk it through face to face, our team is always on hand in-store to help you choose the right setup for your space.