When one of my tanks broke down and my corys ended up from a tank with fine gravel to a plastic container with sand, first thing they did was bury themselves halfway down in the sand. They were like kids. I can argue they were happy in the gravel tank as they were very healthy either way.....but its the joy they seem to experience, or whatever the right word is for fish seemingly being happy, that makes you think twice next time you try keeping them in the same unsuitable conditions...We determine the entire lives of these little creatures and the least we can do is make them happy and keep them healthy.
For the last few months I incidentally I ended up keeping fish in a black above ground indoor pond, and the activity level, colours of the fish, and interaction with me has never been better. The more cover you give them, the more privacy they have, the more they anticipate seeing you and feel comfortable with you around. I have 10 clown loaches now. Anyone that knows clown loaches may know they could be shy fish and run away from you. The other day I put all my hand down to the bottom to pick up a melon I had fed the fish. My baby clown loaches shot straight at me and started nibbling my hands up and down which is very unusual for these fish. They normally now get excited and gather at the surface when they see my head staring down, so do the other fish. I've kept clown loaches for years and have a bunch of 5 year old loaches as well that lived in glass tanks the majority of their lives. They were never as friendly in a glass tank and are now extremely friendly and relaxed with me. Despite the ugliness of the pond in comparison to a glass tank, there's no way I can put these fish back, not the same fish, in a see through box...as they've already seen better.
There's many things we can improve the environment of fish and a bare bottom tank is not one of them. I'd rather stick to a very thin layer of sand which I think is ideal. Whether its act of cruelty or not, I don't know but it is actually counteractive health wise to have a bare bottom because bare glass is known to develop nasty biofilm which is otherwise controlled by the bio-diversity of established substrate. Bacteria and parasites eat each other. There's a food chain for them too, and keeping a bare bottom means creating a super environment for a selected few that become pathogenic. Similar to us humans on Earth....We're the nastiest parasite ever, feed on anything and of everything, of each other too metaphorically speaking
There, fish living in plastic
The amount of substrate I have can't even cover my smallest nail but there's enough for them to browse through. There's a bristlenose in there that's 4-5 years old now. As a matter of fact I barely saw him before he got moved to this tank last year. He's out all the time now.
