What does calcium do to aquarium fish ?

Question

and if there is something in the tank containing calcium, with out removing it, how can you control what it does?

Answer 1

the fish may absorb a bit of it which is fine but the main concern of calcium is what it does to the water.

Calcuim alters the pH of the water to make it harder. Most fish can tolerate a large range of pH but some do better and prefer softer water.

take some water to a pet store they will test teh pH for free, if it's in a tolerable range your good to go.

Almost all calcium in the tank is souced from your tap water. You may live in an area with really hard water or you draw water from a well.

good luck!!