I managed to take a couple of awful pics while changing the substrate in the eels tank today, yeah I know they're rubbish (even for me) but they show the pattern ok....
So does anyone want to hazard a guess at what it is?
Have you seen them before with lines instead of tyre tracks? There was at least one other similar sized tyre track in the same tank at the shop and it had the usual pattern.
Thanks King_eL!!
According to fishbase they only get to 37cm, which isn't as big as I wanted, and may not be big enough to live with my aro and ornate.
Apparently the size on fishbase isn't that accurate. King-eL said he's seen them at around 22", so they might get to a similar size of a regular tyre track. I'm not going to get rid of it, so we'll find out how big it gets in a few years...