Not sure about that, but I would put Israeli carp in my pond at a LAST RESORT! They could really stir up your pond and get out of hand. BTW I think Israeli Carp is a fancy name for the common carp.

Filimentous algae is a seasonal thing in my trout pond. It's fairly excessive early in the season and then just disappears. I do net it out on a daily basis and dispose of it. At some point late in the spring I think the chara takes over and outcompetes the filimentous algae in slightly warmer water. Another factor could be I do add bacteria which can't work well until water temps get up to the mid 50's.

Have you tried bacterial augmentation? How much macrophytes (rooted vegetation) do you have? Manytimes if macrophytes or phytoplankton are scarce than filimentous algae is prolific as something has to uptake the nutrients.

Additionaly do have have excessive shallow water around the edges? If so that will contribute to the problem. Any way you can reduce nutrients going in?

If pigs could fly bacon would be harder to come by and there would be a lot of damaged trees.