Yes it is a Fluval Flex.Btw is that a fluval flex???
Thank you, appreciate it.That's a bristlweworm, or a fireworm, same thing really, they both sting like hell but are good scavengers. If you do want to remove it you can look up a diy bristleworm trap or use a pair of long handled tongs to pick it up, do not use your bare hands, you will end up with a thousand bristles stuck in your skin and be stinging for hours.