Who Gives A Fish Forums

I just set up my first 20-gallon tank and added a few Neon Tetras. The water looks cloudy after two days. Is this normal, or did I mess something up?

Cloudy water usually means a bacterial bloom. Did you cycle the tank before adding fish? If not, you're gonna need to do frequent water changes and test ammonia levels.

landcritter wrote: ↑Fri Jun 27, 2025 12:02 pm Cloudy water usually means a bacterial bloom. Did you cycle the tank before adding fish? If not, you're gonna need to do frequent water changes and test ammonia levels.

Yep, that's spot on. Also, what filter are you using? A sponge filter or HOB? Some setups take longer to clear up.

Don't stress too much! My first tank did the same thing. Just keep up with small water changes, like 10% every other day, and it'll settle. How often are you feeding the Tetras?

Cloudiness can also come from overfeeding. Cut it back to once a day, small amounts. What's your substrate? Some types kick up dust if you didn't rinse 'em well.

Test your water params ASAP. Ammonia and nitrite spikes are dangerous for Tetras. If either is above 0.5 ppm, do a 25% water change. What conditioner are you using?

rivela wrote: ↑Fri Jun 27, 2025 2:18 pm Test your water params ASAP. Ammonia and nitrite spikes are dangerous for Tetras. If either is above 0.5 ppm, do a 25% water change. What conditioner are you using?

Good call. Also, toss in some Seachem Prime if you've got it. That stuff's magic for neutralizing toxins.

Thanks, everyone! I'll test the water today and cut back on feeding. Using a HOB filter and Seachem Flourite substrate. Didn't rinse it well, so maybe that's the issue.

Flourite is notorious for dust. Rinse it under a hose next time until the water runs clear. For now, just let the filter do its thing.

How's the flow on your HOB? If it's too strong, it might be stirring up the substrate. Try baffling it with a sponge or lowering the water level a bit.