Herp Enclosures

Currently I have two turtles (15 ears red??? Mud Turtles) in a kiddie pool in my apartment with heat / Spot UVA / UVB / lamp and two landings to choose. They have a filter cartridge to a friend gave me that great works (filter water and keeps it clean) and I still average about 20 goldfish in the pond for their amusement / diet.

I also have a leopard gecko for 6 years in a 20 gallon long with a heat lamp, sand and calcium bowl of water with some wood and leaves to hide.

And finally, a tarantula (pink hair, I think) in one gallon 5 with newspaper and mulch as well as a water dish.

What I wonder is if any of the conditions above accommodations can be improved (within reason, I do have a backyard or anything bigger than my room in the house) and if so, suggestions? I know that reptiles and Herp this question do not need to neural stimulation that mammals really, and do not need to eat every day, I'm just worried that the turtles are too small or pond The leopard gecko is in a pretty good tank, tarantula really dosn't seem acute care to be fed.

These are my babies, all I really care and you want them to have a very pleasant life. I'm just worried that I'm not giving them everything they need.

Add the red ear slider cuttlebone for extra calcium
My red ear slider like plastic plants, she likes to dig them up and sleep on

do not know about the lizard and tarantula Tho
hope this helps

It seems that you should give advice here, do not ask. I hope that you feed your turtle something besides goldfish.