"mark Bannister" wrote in message
...

They should be getting plenty of sun. And it is possible I don't have
enough fish yet. There are about 15 goldfish in 750 gallons, sized from
quite small to 10" or so. I stepped up the feeding to see if that would
change anything and now I have very fat goldfish but the plants are the
same.

Rule of thumb is atleast 20 gal per full grown goldfish and 100 gallons per
full grown koi, so you can put a max of 37 fish.
As someone else already suggested, plant your plants in clay or soil instead
of gravel.

What I do, is fill a terracotta pot with supersoil potting soil, add in the
plant, then cover the top inch or so with pea gravel.
I personally have never added any fertilizers, but give it a try, maybe it
will work for you.

-S