Schoolers All Staying To One End

[tntprmtns]

I have a 20 gallon tank. Well cycled, check my levels once a week. I have 5 priscilla tetras, 3 cories, 1 pleco, and 1 albino cherry barb( companion passed and have not gotten any in at lfs) I recently added 3 black tetras. They started to school with the tetras and barb. All was well for about 10 days.

Recently I noticed that all the schoolers are staying on the right side of thank. Cories and pleco are acting normally. I double checked my levels and all seemed within normal, amonia was a touch up, so I did a 50 percent water change.

Still hanging on the right. The tetras will come on the left side when I feed there but then move back.

The left side to middle is well planted and the right side has no plants but I do have some air bubles and the heater there. It's been very hot here and my temputure seems to be if anything a touch high but still in the safe zone.

Otherwise they seem normal. Color is good, they react to me when I come to feed. I just can't figure out what is wrong.

Any ideas would be appreciated. I've had this tank about 6 months and it's been pretty smooth so far.

Thank you

 

[brian1]

Try moving your heater to the middle of the tank, a picture would be good...

 

[ColR1948]

I recently posted on this myself and someone said try turning off the air-stone, I did this and hey presto they are swimming all over the tank now.

 

[aquariumart22]

I recently posted on this myself and someone said try turning off the air-stone, I did this and hey presto they are swimming all over the tank now.

+1

 

[tntprmtns]

thank you! I have normal fish again! Airstone off and heater moved. They are happy again.

Thank you

 

[raptorrex]

I always though the best thing was to have your filter, out letting onto or near the heater.
allowing the water flow to draw heated water around the tank.
I notice in-.line heaters are all fitted to the outlet side of your system