Can putting algae cleaner in the tank make fish lay at bottom?

No. This is not true. If you have fish laying dormant at the bottom of the tank, it is an indication that the tank is not suitable for living.

Reasons for this can be:

1) The water in the tank is not treated properly or contaminated.

2) There might not be enough oxygen for the fish

3) The water is too hot or too cold for the fish

4) The tank might be overcrowded