Gravel......

[starscream]

The tank I have now use to be my sisters, when she first got it she put pink and blue rocks in.... I want to change it but idk if I should.... Its a 55 gal tank and there are fish in it..... What do u think?

 

[Gvilleguy]

Hey Transformer dude,

The majority of helpful bacteria that keep your tank water clean reside in the filter of the tank. However, there is also likely helpful stuff in the mature gravel. You would most likely be okay with swapping it out, but if you wanted to be safe, you could plan to replace just half of it at first. Then let the tank settle for a day or two and test the water to see if you are getting any ammonia or nitrite before swapping out the other half.

 

[matt_storey]

Why not go for sand? Have you got a picture of the tank?