How to fix a cloudy fish tank when chemicals aren't working?

Thanks for reaching out about Fishy. A UV sterilizer will only help if a bacterial component is adding to the cloudiness. More intense water changes are the best way to remove nitrates. Monitor feeding to limit excess, vacuum bottom of tank to remove degrading detritus. Good luck.

Weekly to biweekly 25 % water change can keep the water healthy. Also, monitor the temperature and water chemistry and adjust as needed. You many consider wiping down the sides often to prevent algae from Growing on the glass. Best of luck and thank you for using Pet Coach.

The cloudiness can be due to elevated ammonia or nitrite levels or algae blooms. If the tank was previously cycled, the water change may have disrupted the nitrogen cycle resulting in cloudy water. Check the water temperature and chemistry. It is okay to cycle a tank with a turtle in it. They are hardier than fish and can withstand the elevated ammonia and nitrites until the tank chemistry "settles" down.

This can be due to micro bubbles from the filter. This will typically resolve in a few days. If the filter outflow creates a large amount of turbulence, try decreasing the flow rate. Another cause can be a bacterial bloom. This is a common occurrence after a water change and is caused by elevated ammonia levels or large amounts of organic matter in the tank. Either can feed bacteria and promote overgrowth. Check the filter media and rinse it, with tank water not tap water, if necessary. Check the water chemistry using a home test kit or by submitting a water sample for testing. The local Petco may do this for free or for a small fee. Ammonia levels, ideally, should be 0 ppm. Perform a partial water change if necessary. Use only conditioned water that is temperature matched to prevent stress or shock. Condition the water before pouring it into the tank. Remove any dead or dying plants, limit lighting, monitor water temp and don't overfeed. This will decrease the chance of a bloom occurring due to excess organic matter. Luckily, bacterial blooms are not harmful to fish. They can be frustrating, but they do clear up eventually.

I would recommend checking your water quality first to evaluate your ammonia, nitrite, and nitrate levels. With new aquarium set ups, it is common to have issues with water quality as your bacterial populations are getting established. I am not sure if you have fish in your tank already or not, but if you do, please monitor them closely for signs of distress, as this can occur with elevated ammonia and nitrites. Signs to look for would be swimming very fast (hyperexcited state) and trying to jump out of the tank. I hope that gives you a place to start, and good luck!

If you put an Oscar in with your Tetras, they will be harassed and eventually eaten. Use a home test kit or submit a water sample for testing to check chemistry. Aim for 0 ppm ammonia and nitrites with a nitrate level of 20ppm or less. It can be slightly higher if you have live plants. If there is still ammonia present, the tank is still cycling. The cloudiness may be micro-bubbles which will eventually resolve or it could be a bacterial bloom which will also resolve once the tank has cycled.

Thanks for reaching out. Have you tested water quality for pH, ammonia, nitrite and nitrate. Correct problems. Don't see any signs of external lesion on the pictures, except fine erosion, and possible gravid fish. A veterinary visit is probably needed to trouble shoot for disease. Randomly adding chemicals to the water could have detrimental effects. Good luck.