Dog-proof aquarium setup for multi-pet homes

A dog repeatedly knocking over a nano tank is genuinely dangerous — broken glass, water damage, and stressed or dead fish. The solution here isn't a better position for a light tank, it's moving to something heavy enough that bumping it does nothing. Before we get into that though — the most important concept before buying any new setup is the nitrogen cycle. A tank needs to fully cycle before you add fish, and skipping that step is the number one reason fish die in new tanks. So while you're sorting out the stability problem, that cycling time actually works in your favour. Quick questions: how big is your dog, and what kind of fish were you keeping in the nano?

A Labrador tail at full wag generates a surprising amount of force, so a 20 litre tank on a shelf was always going to lose that fight. What you need is a tank that sits low, on its own dedicated cabinet stand, with enough water weight that a dog collision just doesn't register. At full capacity, a 57 litre tank with its stand weighs around 70kg — no Labrador is moving that. What's your budget roughly, and are you happy to go up to that kind of size, or would you prefer to stay smaller?

In that case I'd go with the Fluval Flex 57L with its matching cabinet stand. The tank itself has a curved front, looks genuinely attractive in a living room, and the cabinet is sturdy hardwood construction that keeps the whole unit low and planted to the floor. A betta will thrive in 57 litres — far better than a nano — and the included filter and lighting are both good enough that you won't need to replace them. The Flex's filter is particularly betta-friendly because it has an output nozzle you can angle to reduce surface agitation, which bettas prefer. Combined with the weight of a full cabinet setup, your Labrador can career into it and absolutely nothing will happen to the tank.

No — and this is where that nitrogen cycle I mentioned at the start really matters. A new tank has no beneficial bacteria to process fish waste, so ammonia builds up quickly and can kill fish within days. You'll need to cycle the tank first, which takes three to six weeks. The quickest way is to use a bottle of Seachem Stability or similar beneficial bacteria product, run the filter with some fish food added daily to create ammonia, and test the water with an API Master Test Kit until ammonia and nitrite both read zero and nitrate is present. Once it's cycled, move the betta across with some of the old tank water. Your shrimp can follow once you've confirmed parameters are stable.

Good choice. One practical tip: when it arrives, put the cabinet exactly where you want the tank permanently before you fill it — moving a full 57 litre tank is miserable and you risk leaks. Get the cycle running, take your time with it, and you'll have a setup that survives anything a Labrador throws at it.