Cardinals not swimming in the open

Hey guys..
I have about 20 Cardinals in a 55gal.
Recently they are staying under the filter intake and not schooling in the open.

Wondering if I have to many plants or decor needs moved around again ?
I really don't want to redecorate the tank :/
Any ideas ? Experiences ?
Thank you

 

How long have you had them for? Were they schooling before? When was the last time you did a water change?

 

Any full tank pic ? Light substrate ?

 

They way is see how schooling fish works...when they’re packed tight together and at a standstill something spooked them or they don’t feel comfortable at this time. They’ll eventually get over whatever freaked them out.

When they are not swimming in schools and just swimming around themselves they’re ok and nothing is wrong.

 

What other fish do you have with them?

 

Any full tank pic ? Light substrate ?

yes I do.

How long have you had them for? Were they schooling before? When was the last time you did a water change?

I've had them for years.. I did add 5 more a week ago.
Yes they would school before.
they would zip about the tank a bit.

Last water change about 3-4 days ago.

What other fish do you have with them?

1 clown pleco-
18 cardinal tetras.
2 mystery snails.
1 blue ram
2 nerites.- 6 kuhlI loachs-
2 sterbaI cories - 5 ghost shrimp -5 sidthmunkI loach -1 bolivian rams
1 african dwarf frog -12 amano shrimp- 2 assassin snails. 5 candy cane tetras.
6 pygmy cories.
Fully/heavily planted.

 

You got a lot of bottom feeders. You should add more sterbaI cories. You also have so many fish, they are likely stressed/feeling crowded.

 

They will be okay. They show vibrant colors what's a good sign.

 

You got a lot of bottom feeders. You should add more sterbaI cories. You also have so many fish, they are likely stressed/feeling crowded.

I am aware of the sterbai, however they're going to start at the current numbers.

The tank doesn't appear crowded but that's a consideration I will receive.
Would opening decor help or see if it resolved as fashooga stated ?

 

They will be scared of rams and sidthimunkis.

 

I know Neon tetras are schoaling fish, not schooling. Could these possibly be too?

 

I know Neon tetras are schoaling fish, not schooling. Could these possibly be too?

I'm not really sure if the difference between the two ?
I think I found the answer to my own question.

The tank is placed next to the hallway and most traffic goes by the left side of the tank. Which the activities of daily basis seen to scuttle them to the right side of the tank.

 

Very well could be your answer. Just an FYI... schooling fish stay close together, changing direction at the same time and remaining in a group. Schoaling fish like to stay in close proximity of each other, but will swim off on their own.

 

Moved a few things around and they seem to be acting better. Still staying to the right but more pleasant than a ball of fish.

 

Add a predator that’ll get them too school nicely.

Just kidding

 

Mine tend to do their own thing. I've only got 9 but on occasion you'll see 6/7 together and a couple of on their own elsewhere in the tank.

 

The only aquarium fish that I've seen "schooling" are rummynose tetras. Others might just group together, or feel comfortable with lots of their own school.

 

Since I upgraded the tank they seem to group or school better.
Maybe it's coincidence, but they are close to each other most of the time now.