The tojanida is one of those things that's just too weird to make jokes about. Where to even start? Its ridiculous arrangement of limbs? Its strange eye-things? Its deformed mouth? (or at least, I hope that is its mouth)
Ah well, let's just start the assignment.
3 outsider RHD, small size, and bonuses to each stat that's not intelligence or charisma (with the former being average and the latter incurring a small penalty). Natural attacks are two weak claws and a quite strong bite. As is to be expected of an aquatic outsider, its swim speed is high. Sadly, land speed is a joke. Immunity to two energy types and resistance to two more is useful, and to a lesser degree all-around vision is as well.
As for offensive special abilities, there's improved grab (of questionable use on a small creature) and the ability to either duplicate Fog Cloud (underwater) or briefly blind foes with ink (out of the water). The blinding may be worth it as a short-range debuff, the cloud will hamper your teammates as well.
Are juveline tojanidas unplayable? I don't think so. The chassis is pretty neat compared to its cost, and especially in more aquatic campaigns various builds are viable. +0 seems okay.
Medium size, slightly more strength, a slightly harder shell, and slightly stronger natural attacks, and all that for the low price of 7 RHD! How about no.
15 RHD does not make up for what's just another size increase. -0 here as well.