Marine Tank Help!!!

I have a 2nd hand marine tank, its been going for about a month now and ammonia reads 0, nitrite reads 0 and nitrate is about 25ppm. Should i perform a water change before i add my next desired fish (a bicolor blenny)? the tank already contains 3 green chromis added 2 weeks ago when reading were as they were now (with the nitrate slightly lower). Future fish incld 1 maroon clown and 1 scissortail goby.

PS i posted a post about this on the old message board but i cud not get it onto this forum!

THANKS!!!

 

No, you shouldn't need to do a water change before bringing in your new fish. If you do add new water, your nitrate, nirtite, and ammonia levels could change and you'll have to wait even longer before adding another fish. You should be fine.