So, just to follow up with yet further evidence of my lack of any skills in the craft/creative department, here are photos of the finished Tuna Fish Who Can't Carry a Tune (complete with hedgehog sidekick).
Frighteningly authentic isn't it? I am frankly relieved to get the ensemble out of the house before we are overrun with either trawlers or protected species environmentalists.
Ultimately there were no fins. They proved to be a stretch too far for my limited abilities. Although I did manage to embellish the t-shirt even further with 8 mini photos of tuna, which gives it a really polished finishing touch I'm sure you'll agree. (What do you mean, you can't see them? Just squint and move your head slowly side to side...they're so lifelike you can almost convince yourself you are staring at a school of tuna swimming in the ocean. Honest.)
There was a funny moment just before this picture was taken. As I went to put the t-shirt over Captain Underpant's head I realised that when glueing all the authentic fish-like embellishments the t-shirt had been laying flat on the table...and was now completely stuck together. What a novice. Thankfully I manage to successfully separate the front from the back of the t-shirt without any collateral damage.
It was all worthwhile just to see the look of pride on Captain Underpant's face when adorned with his mother's masterpiece...
He was not particularly impressed.
Well, I guess that makes two of us.