Unexpected Growth

[Echinoderm]

Please help. I have a 15US Gallon tank with 3 Dwarf Puffers, 1 Corydora, and 2 Java Ferns. There is sand substrate and a log. The tank was absolutely spotless. I carried out weekly water changes and kept everything consistent.

I had to go away for about 5 days and a friend fed my fish for me. Now there seems to be something green growing in one part of the sand and on two of my clay pots. There is also a little fuzziness on one fake plant. It looks like this can get bad fast.

I am doing a water change tomorrow. I will vacuum that area of the sand and scrape the growth off the other surfaces. Is there anything that I can put in the water that will be safe for my fish? Should I add a little bit more aquarium salt than usual? Are there any changes to be made to the water chemistry?

Thank you.

 

[snowflake311]

No salt if you have Cory cats you should have 3 corys. Could you post a photo? Sounds like algea to me. Clean it keep up water changes. The fish might have been over fed. So once you get everything back to normal it should be fine.