Besides the salmon and halibut that I have in the fridge, I have a large package of barbecue unagi that I had ordered to do sushi with.   And I was surprised at how large the pieces are,  - about 16 to 18" long and 1-/14" wide.     But that makes sense; unagi is eel, a freshwater variety, from Japan.
I am thinking about doing something other than sushi with some of it.   I just did all that egg sushi and figure to wait to do more sushi, till sometime later.   So, no, you won't see a fish sushi entry in the challenge from me, not with only 6 possible entries.