Floating plants.

[Mr.catfish]

I need fast-reproducing floating plants that my goldfish does not eat.

And how can I make my bristolnose pleco stop chasing my corydoras and damaging their fins?

Edited April 11 by Mr.catfish

[T. Payne]

The only floating plant my goldfish do not care to ear is dwarf water lettuce. As far the pleco goes, is it a male or female and what size aquarium is it in?

[Mr.catfish]

it's 60 liters and it's a male because it is starting to grow a beard similar to the picture but it's still very small/young so I am unsure. This is my aquarium. 

 

[johnnyxxl]

You can try rearranging the decorations in the tank, and hope that helps.  The pleco may feel territorial due to the size of the tank.

[Mr.catfish]

Where do you recommend to rearrange the decorations?

[johnnyxxl]

If you change how everything is and make sure no direct line of sight, you can make things less stressful.

[Odd Duck]

I’ve had bristlenose plecos in with cories and never had a cory show any fin damage. It likely is something else entirely.

Bristlenose plecos (the usual species) are very large for that size tank, by the way.  There are species of pleco that have bristles on their noses that are smaller but the hybrids we usually call bristlenoses can get 6-7” long for males.  I have 2 that are about 6.5” in my 100 gallon, mostly nanofish tank. That tank also has about 20 cories of 2 species and I’ve not seen any of them show any fin damage so far.  The plecos have been in there close to 3 years now (I’d have to check pics to give you a date).  The oldest cories have been in there longer and the youngest is only a few months old - hatched in the tank.

My big boys are territorial to each other and occasionally scuffle a bit (shoving match only) but they don’t even bother to do anything to the cories except occasionally push them off the bit of food they want.

Do you have any other fish in the tank?  Of any sharp edges on any decor?

Whoops!  Just looked back at your pic and saw the goldfish. They are kind of notorious for randomly nibbling at whatever catches their eye.  I once had to remove a dead cory out of a fantail’s mouth to save the fantail. Those goldfish are far more likely to be the culprits for fin damage on cories.