This is an add-on thread, and I know I didn't cover a lot so please add!
Freshwater Substrates
Different people choose different substrates when it comes to freshwater aquariums. The two main substrates are sand vs. gravel. There are several pros and cons to each one.
First off I want to say that it doesn’t matter what color you want to buy. If you want pink gravel it makes no difference to fish that black gravel or beach pebbles. If you want to replicate the fish’s natural environment of course you will want to buy more natural of a substrate. And then some fish need finer sand/gravel (i.e. digging species or bottom feeders like kuhlii loaches, corydoras, etc.) and others prefer larger substrates (like oscars who never stop messing around with gravel, though oscar tanks most of the time have very little gravel because it can get hard to clean.)
When you first pick out substrate, take time to think about what fish you’re going to want for your aquarium. As I said earlier, most catfish prefer fine gravel or sand. If all that you are going to get, for example, are danios and barbs, the gravel size doesn’t matter as much. If you do want catfish or fish that bury themselves do use small grained substrates.
Pros and Cons of Gravel
Pros: Cleans easily, comes in many colors, is often cheap, good for species like large cichlids that mess around with gravel
Cons: Isn’t as natural as sand much of the time, not good for bottom feeders, food and waste can get trapped down into gravel
Pros and Cons of Sand
Pros: Looks more natural than gravel, great for bottom feeders and diggers, waste sits on top of the sand
Cons: Anaerobic bacteria can get trapped in pockets and thus the sand needs to be stirred sometimes, waste sitting on sand can get annoying, somewhat expensive
Peat substrate: Peat substrate should only be used for species like killifish or for spawning.
Freshwater Substrates
Different people choose different substrates when it comes to freshwater aquariums. The two main substrates are sand vs. gravel. There are several pros and cons to each one.
First off I want to say that it doesn’t matter what color you want to buy. If you want pink gravel it makes no difference to fish that black gravel or beach pebbles. If you want to replicate the fish’s natural environment of course you will want to buy more natural of a substrate. And then some fish need finer sand/gravel (i.e. digging species or bottom feeders like kuhlii loaches, corydoras, etc.) and others prefer larger substrates (like oscars who never stop messing around with gravel, though oscar tanks most of the time have very little gravel because it can get hard to clean.)
When you first pick out substrate, take time to think about what fish you’re going to want for your aquarium. As I said earlier, most catfish prefer fine gravel or sand. If all that you are going to get, for example, are danios and barbs, the gravel size doesn’t matter as much. If you do want catfish or fish that bury themselves do use small grained substrates.
Pros and Cons of Gravel
Pros: Cleans easily, comes in many colors, is often cheap, good for species like large cichlids that mess around with gravel
Cons: Isn’t as natural as sand much of the time, not good for bottom feeders, food and waste can get trapped down into gravel
Pros and Cons of Sand
Pros: Looks more natural than gravel, great for bottom feeders and diggers, waste sits on top of the sand
Cons: Anaerobic bacteria can get trapped in pockets and thus the sand needs to be stirred sometimes, waste sitting on sand can get annoying, somewhat expensive
Peat substrate: Peat substrate should only be used for species like killifish or for spawning.