Hey ,good to see a new Tau player
.One thing to note is Tau are getting a new codex this month so rules might be shaken up but I'll still tell you what I think of this list.
First you have way too many
FW .2 units of 12 buffed with ethereal/fireblade(I prefer ethereal) is enough for anti infantry .Also devilfish's are,I feel , are only good with small squads(if good at all).Really I usually have 2 12 man w/ethereal and maybe kroot screen for protection.
Now one glaring thing in this list I don't like.You're taking piranhas
.I see you haven't given them
FB so they're just MORE anti-infantry with
FW and die really easy to anti tanks fire .I got one in the Tau battle fore and it right now is chopped up for the base of my riptide.
Now finally the elite slot .If I do my maths right 2 PR are better than twin-linked ,might also be good to put buffmander in to help further.People on here also hate mixing and matching crisis weapons but I still do it for competitive lists to pretty good effect.In a 1500 point list you would want a riptide with Ion and fusion for
MC,
TEQ and vehicle killing.I personally love my riptide as it's my favourite model.