Help! Not Swimming/Eating/Interacting at all!

[katequang]

So I did a "full" water change two days ago (by full I mean I switched out about 3/4ths of the water, cleaned tank, etc.) and I moved my betta's tank to my daughter's room, which has sun in it the entire day. Before, he was in my room, which is dark all of the time besides his light, which we had turned on.

In our room he was thriving. He looked happy, swam around and loved to "greet" anyone who came in the room. Since the switch, he has drastically changed. His tank is full of goopy white strings, a lot of them attached to the heater. He has been hiding behind the heater and refuses to eat! He only occasionally floats to the surface for air. He has his fins tucked up close and he's gone from bright red to dark. He looks worse than he did when we got him!!! His water is also very thick feeling.

We are using natural rocks in his tank, and I thought maybe they were affecting it. Or maybe our heater is bad? Or the sunlight is too intense for him? Oh, and he is in a 5 gallon tank, small heater, natural rocks, no filter.

I am very concerned, if anyone could help me figure out whats wrong, I'd love any help I can get ASAP.

[vilmarisv]

The first thing you should do is change the water and make sure you're adding the correct amount of conditioner.
Is your heater working? What's the temperature of the water?
If you don't have a filter, 100% water changes are a must beause your water has no movement and it's not being cleaned by a filter so bacteria can bloom from one day to the next.

[bluefishy123]

Also make sure he's not under direct sunlight because that affects the temperature of water. Like vilmarisv said, first and best best would be change water/ check water condition. The goopy white strings might be from algae bloom due to increase sunlight. The fish might also be stressed from the move. Give him a few days to get used to the new surroundings.

[katequang]

Hello, thanks for your great replies. I was really concerned so before I got any answers, I did a complete tank clean, put him in a temporary plastic tank, and scrubbed his tank with water. During cleaning, I was in the process of washing his decor and started on the rocks. When I moved the rocks in my hands I felt fuzziness, and I realized the rocks had actually started to grow black mold. Each and every rock had mold on them. I bought these "natural rocks" at the Dollar Store, and since they looked like rocks off the ground, I assumed they were safe for a tank. Since removing these rocks the water has stayed (almost) crystal clear! No white strings or cloudiness.

We've also moved him back into our room. His tank generally stays around 74-76, I'm not sure if my heater is doing a perfect job as it only turns on if the water reaches under 74, but it's definitely better than not having one.

Also, I did not realize that I could do 100 percent changes, as guy at Petsmart told me it'd stress him out. Now I know! Thanks!!!

Pete has made a 100 percent turn around in a few days. He looks healthy, vibrant and possibly happier than I've ever seen. I am so embarrassed that I did not realize these rocks were toxic before. So glad he's okay and thanks to you both for your help.