Question

So I learned osmosis and
Marine fish and Freshwater fish

as I know, for the osmosis, water follows higher solute.
For example, when I think about the hypertonic,
I think like this :
because surrounding has higher concentration,
water goes out.

For hypotonic,
because cell(?) has higher concentration than surrounding,
water get into the cell.

But when my lecture was talking about
Fish for Marine and Freshwater, my knowledge was messed up.

the lecture say that fish in freshwater need to maintain a higher ion concentration than surrounding, and they said that the fish in freshwater is hyper osmotic regulator (maintain a hypertonic state)

So what I cannot understand from here is
if fish has more concentration than surrounding,
shouldn't this fish be hypotonic?

why lecture is saying
environment is hypotonic and fish is hypertonic or hyperosmotic regulator????????????

plz explain this on screen
I usually have a really hard time to read with hand writing