Scared fish, how to help?

[Fauxrenier]

I have an 8 gallon planted aquarium with a few female guppies I kept from the final litter (the mother’s ok just separated the male out as it was getting overwhelming). They had always been around and would swim right up to the top at feeding time. About a month ago I caught my 3 year old open face palm the glass hard. He loves the fish so I know he didn’t do it maliciously. They haven’t been the same. Every time I walk in the room they bolt to the back corner under the sponge intake, behind some plants. It’s unfortunate cause they just started getting blue color in their tails and dorsal fins like their mother. 
is there anything I can do to coax them out or is it really just a matter of time? I assume they’ve been eating since they’re not dead and I’ve been trying to get the food to fall around where they hide.

[Keeg]

With shy fish, its always best to just give them time. Sit next to the tank with the tank light off and the room light on. Do whatever, read a book/ watch a show. Just being there is enough to change their behavior. You could throw some food away from their hiding spot to entice them to come out while you're present. 

[Atitagain]

Has anything else changed with your tank or surrounding area? Change in decorations, lighting, circulation, a new fish, ect… Even changes in the surrounding room; new tv close creating new sounds, different light, something creating shadows( fish very scared of shadows) 

most of these will balance out with time. But really think about it’s not just their tank it’s the surrounding environment as well. IMO it’s not likely the one bang on the glass is still causing this behavior.

[Guppysnail]

On 8/30/2021 at 5:02 AM, Atitagain said:

Has anything else changed with your tank or surrounding area? Change in decorations, lighting, circulation, a new fish, ect… Even changes in the surrounding room; new tv close creating new sounds, different light, something creating shadows( fish very scared of shadows) 

most of these will balance out with time. But really think about it’s not just their tank it’s the surrounding environment as well. IMO it’s not likely the one bang on the glass is still causing this behavior.

I agree with this. My cat forever head butts and slams into my stand and frightens my one sorority tank. They are fine shortly after. Try rearranging their furniture and plants if you cannot find what has changed in their environment.  Place something over the front glass cardboard etc while doing it so they are not stressed while you are rearranging.  That sometimes helps other fish to reset whatever has them spooked. 

[Fauxrenier]

Thanks for the suggestions. I did trim out a large chunk of over grown christmas moss shortly before this, like maybe a week or two. I thought I would be giving them a bit more space to swim. Maybe I just removed a 'security blanket'. When it regrows out maybe they'll be a bit more comfortable again. There was also the loss of their Amano tank mate before the moss trim. Started thinking this weekend about replacing her this last weekend but never made it out to the LFS.

[Guppysnail]

Also sometimes after a scare event or tank death a large water change removes the fear hormones released and whatever “scent??” The death produced