I would encourage all fish keepers to gain an understanding of the nitrogen cycle as this will help you understand exactly what is going on inside your tank and how you can deal with water quality problems should they arise.The simple answer is yes, an aquarium must be cycled properly before you can safely add your fish. It doesn't matter whether the tank is 15 gallons or 500 gallons, it's still got to be cycled. If you were to simply fill your tank with water and then add all your fish at once then there would be such a massive buildup of ammonia, the chances are your fish would be dead within a few days.Traditionally, there are two ways to cycle a fish tank. Both methods will involve introducing ammonia into the tank which will be the food the bacteria need to survive. The most common method of cycling an aquarium is to use small community fish that produce the ammonia themselves. A kinder, more acceptable way to cycle a fish tank is to use a method called the "fishless" cycle. This also involves adding ammonia to the aquarium, but as a name suggests you do not use live fish. In this article, we are going to use fish as it's probably easier for a beginner to undertake, and we wouldn't be happy with youngsters handling pure ammonia as it can be dangerous. If you would prefer not to use live fish then read this article on how to carry out a fishless cycle.We would recommend that you use small community fish like the Barb. The Tiger and Cherry Barb are absolutely ideal as they are quite a hardy species of freshwater fish and unlike some more sensitive species, won't turn belly up as soon as they are exposed to ammonia. If you are cycling a very small tank less than 20 gallons then you are probably better off using much smaller fish like guppies or neon tetra. Your fish store should be able to give you advice based on what fish they sell.It's important not to add too many fish as this will create a large ammonia spike very quickly which will probably just kill the fish within a few days. For a 55 gallon tank, 10 barbs would be appropriate. For a 75 gallon tank, you could go up to 15, for 100 gallons plus, you're looking around 20 upwards.It's become quite popular to kick start the cycling process by seeding your new aquarium with biological media that already contains live nitrifying bacteria.
Canister filters are typically much more powerful than other filters because they can accommodate more filter media and hence, perform all these filtration best. However, canister filters are more expensive than other filters used for the same tank sizes and usually chosen for medium to large aquariums upward of 30 gallons. They are the popular choice for stocking many saltwater or freshwater fish that requires a good filtration system to do well.
Before You Buy an Aquarium Filter - The Spruce
I find that my eheim 350t works incredibly well in my planted aquarium, and gets rid if the need to put in an inline heater, or a heater in the tank. It has trays and trays of biological and mechanic filter media, and works for all kinds of freshwater aquariums. I’ve used many clip on, and external canister filters as well as in tank filters after 8 years of fishkeeping, and this is honestly the best I have ever used.
filters are becoming increasing popular in freshwater aquariums.
I have a planted 75 gallon freshwater tank with many rainbowfish and a cranky old angelfish. I find getting into/out of canisters a little cumbersome, and time has become a bit more dear now that I have kids. So I run my old classic Eheim (165gph) with biological media+ an Aquaclear 70 (300gph) with 1 sponge and filter fluff in a bag. That way I get the benefits of a slower flow canister for bio (which doesn’t require much maintence and contact time is the key with bio filtration), and the ease of being able to change filter fluff weekly (takes only 2min- hence gets done routinely). With 30% water weekly water change my tank is crystal clear, and my nitrates are always
Fish Tank Filters - Jack Dempsey