How to Stock Your Tank

It’s all very well to hear people talking about the beauties of an aquarium, how to maintain adequate pH, keeping nitrate and phosphate levels adequately balanced, and so on … there seems to be plenty of technical detail available!
But what about the actual fish? How do you choose which ones you want? How do you know whether they’ll be too big for the tank when they grow up, or whether they’ll be compatible with your other fish? How do you find out how to stock your tank?
Here is a quick rundown of the things you’ll need to bear in mind when choosing fish for your tank, as well as a brief look at a couple of the more common types of tropical fish. Hopefully it’ll give you a good idea of where to get started!
Freshwater vs. Saltwater
Obviously, the water type is different, but what does that actually mean in terms of the kind of aquarium you’ll end up with?
Specifically, freshwater tanks are generally recommended for beginner aquarists – especially if children are going to be involved in looking after the fish.
This is because freshwater fish are much easier to look after, and are generally more resilient to less-than-perfect water quality and fluctuations in temperature (and, really, all the sorts of mistakes that beginners are prone to make!). In general, freshwater tanks are both cheaper and easier to maintain than saltwater ones.
Saltwater aquariums often have more colorful fish, but maintaining the chemistry of a saltwater tank is a pretty finicky business, and is best undertaken by someone well-versed in the lore of fish-keeping.
What to think about when choosing your fish
Unfortunately, choosing fish for an aquarium isn’t as simple as you might think. You can’t just go into a pet store and select arbitrary numbers of the fish that you find the most appealing – you need to invest some forethought into your tank to ensure that your fish lead happy, healthy lives.
Some things to think about:
  • Fish size. When you buy fish, they’re usually babies. Some will stay about the same size, but other will grow much, much larger – so you’ll need to bear the size of your tank in mind! As a standard rule of thumb, always buy for the adult size. If there’s no guide on the tank or if you’re unsure, ask the assistant. This is really important, because fish are sensitive little creatures: if they’re subjected to overcrowding (which happens when fish are too large for their surrounds), they can get so stressed out that they die. Really.
  • Recommended diet. Not all fish dine equally – some fish eat live food, some eat frozen food, some eat flakes, and some will eat anything (but don’t rely on that last one when it’s tank-stocking time!) Because different fish eat different things, unless you’re prepared to invest time each day in measuring out the accurate quantities of various fish foods, it’s best to get fish that eat the same thing. It’ll make it easier and less expensive for you to take care of your new pets (and will ensure that the kids can participate, too, if they want to get involved).
  • Compatibility. Contrary to popular belief, fish do actually have personalities – and some of them can get pretty aggressive. Many tropical fish have well-deserved reputations as bullies: they can nip the fins of other, more peace-loving fish, they can ‘barge’ smaller fish, and they can get into fights (which are frequently pretty vicious). To eliminate the likelihood of your fish getting into scraps, you should aim to buy fish that have mutually compatible personalities – which means, no territorial fighting fish in with a school of peace-loving roamers!
  • Water temperature. Just because the dozen or so species of fish in that wall of tanks in the pet store are all labeled ‘tropical fish’, doesn’t mean that they’re all tropical fish from the same region. Different fish thrive in different temperatures – and because you can only have one temperature at a time in your tank, it’s best if you choose fish that are comfortable in the same temperature range.
  • Life expectancy. Some fish live for upwards of ten years – which is a pretty serious time commitment! If you’re a free spirit who likes to roam about (and, let’s face it, tropical fish tanks don’t normally go down so well when you’re trying to thumb a ride), consider how long you’re likely to want to keep this fish tank for, and shop accordingly.
So what types of fish can I buy then?
Shopping for tropical fish is fun! As long as you’ve got your tank dimensions figured out and know basically how much money you want to spend (and have perhaps printed out the above list, to take with you to the store), grab your wallet and head to the pet shop/fish breeder. One of the best parts about keeping a tropical tank is that the beauty of the fish doesn’t depend on the size of your checking account!
Some common breeds that you’ll likely encounter:
  • Clown Loach. Clown loaches are colorful, lively, and humorous fish with plenty of quirky personality traits (like lying on their side when resting, and making loud clicking noises when they eat!) Clown loaches do best in schools, so if you like them, get at least three or four. These fish grow between 6 and 12 inches – they’re pretty sizeable! – and prefer to eat meaty food.
  • Congo Tetra. These peaceful fish are popular choices for beginners, as they’re very brightly colored and like to flash around the tank in divertingly attractive schools (again, you’ll need to get more than a few of these to keep them happy). These are a medium-sized fish, generally growing to around 5 inches in length, and require a minimum of 30 gallons of water for adequate swimming space. Tetras love clean water, and lots of live plants to dart around and hide behind, but aside from this they’re pretty easy-care.
  • Elephant Nose. These are really amazing fish to look at – they have a long, protuberant ‘trunk’ for a nose (hence the name) which they use to hunt small live food - although they will also eat frozen and flaked food too, if it’s all that’s available. They grow to be about 8 inches long and need a sandy, gravelly bottom on the tank. These are fairly territorial fish, but will do fine as long as the tank isn’t overcrowded.
  • Tiger Barb. These fish derive their names from the characteristic black barring (‘tiger stripes’) on their flanks. They’re very striking fish, but they can be quite aggressive toward other species (they’re known as fin nippers). Aggression is minimized by keeping them in schools, where they’ll be distracted from the other fish in the tank by working out the necessary hierarchy among themselves – it can be pretty diverting to watch! Tiger Barbs grow to about 3 inches and need plenty of space for schooling. They’re omnivores, so they eat all types of food: the one feeding rule is to do it regularly, to avoid aggression!
Further Reading
For more information on the technicalities of keeping a tropical fish tank, check out Katy’s Tropical Fish – A Complete Guide. As the title promises, it’s a complete compendium for the responsible fish-keeper of any experience level, and is packed from start to finish with valuable gems of relevant, detailed, and easy-read information.
Katys Tropical Fish