So a 10g tank with 4 Cories and a Rubberlip Pleco ?
A. What species of Corydoras ?
B. Please consider returning the Pleco. A 10g is much too small for ANY Pleco.
From Planet Catfish :
" temperature: 20.0-23.0°C or 68-73.4°F
Other Parameters: Has more stringent demands on water quality than many plecos and requires highly oxygenated water. Medium hard water is also beneficial.
FeedingOmnivore. Will eat algae and small live or frozen food. Some individuals can be weaned onto pellet food although this usually takes some effort and trial and error on the part of the aquarist."
C. From your other post, it looks like you are just starting your cycle ? I would NOT add more fish until your tank is cycled and the Pleco is rehomed.
I know your Pleco looks small, but they are poop machines and a new tank doesn't have much food for them.
What are you feeding ? And do you have a pic of the whole tank ?
I love Cories, so I know you want what's best for them.
For now keep up on Water Changes ( PWCs) and keep testing your water.
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