That cuttle does look like a mature bandensis! Pretty neat I think. I'll try to get a shot of it from a distance for comparison sake.
One of the secrets to quality in aquarium photography is quantity! Just the way it is.

Flashes bring their own host of issues, one of the most important is white balance. Sadly, with many all in one cameras, your ability to tweak those settings is limited and you end up with not so great results. FWIW, I use a remote flash so I get yummy, dramatic, non reflective results and I can also move the flash further away to change the intensity. I adjust white balance with a nifty thing called an expodisc. Basically, you take a picture through the expodisc (its like a lens filter) and then set white balance to that picture. The bestest advantage to a DSLR IMO is the ability to shoot in RAW. RAW allows easy tweaks to things like exposure and shadow quality - really pretty amazing.
Well, that was blathering! It just nice to ramble at a non sick little girl (guess what I have been doing the last two days!)