Swimsanity!

I did this solo and I prefered to use the (literally translated) swimming tank , perhaps this works with the mooba-suit too.

While fighting the Boss Fight:
I stayed in the middle and focussed on loading up my ultimate/ unleash.
The Tank has more Energy, (works like a shield) a powerful attack and while I was sitting in a tank the squids passed and didn't attack / stunned it.

I started to dive in the bottom tunnel ( IMO the hardest), followed by the top left tunnel and at last the top right tunnel.

I hope this helps.