mold growing in our 150 gallon fishtank

Question

fish tank   We had Oscars in our tank and little by little they all died. So instead of replacing them right now we purchased a catfish and semi aggressive community fish. We have noticed what looks like allege or mold growing in out tank. My husband cut down on their food, did a couple of water changes and now has for the third time used Algafix. As you can see from the pictures our tank is now cloudy and it seems like what ever is growing is still growing. we are not sure what we should do. Can you help us?

Answer
Sharlene,  This is not mold it is a normal algae growth in a healthy tank. As long as you are siphoning your rocks they will stay somewhat clean but, light color aggregates are not going to stay that way once your tank is established. Especially with meat eaters and larger fish. If it is by a window put a background on it and don't keep the light on all day and you should be ok. If it is bothering you, you can change the stone. If you do, do it now before you restock the tank and let your bacteria settle back into your stone and give your tank a little time to cycle out. A week or so. Do not do a large water change if you change stones for a month or so also. I am a firm believer of not using chemical if you don't have to. Them products won't help you. Mold is usually white and stringy or web like and is mostly a problem in planted tanks but harmless just something a good cleaning takes care of. Good Luck, Tina