I don't know what "too strong" would exactly look like enough to stress him out.
He does swim around his new filter exploring

but his black/blue plant (the tips) are moving a bit in the water
the water isn't swirling but you can just see the debris floating around in a swirl
He seems to be able to swim but prefers to stay in the front near his thermometer


How would I know when it's stressing him out?