Hena, my math suggests that 6x FW would be ~150, while 3x DFish would be ~75, or a total of
225
The suggestion for reducing some of the infantry formation sizes should be done in conjunction with the notion of forcing the Tau to activate the infantry in pairs through *Co-ordinated action* precisely to reduce the 'popcorn' effect. Note, I am unsure just how powerfull this would be as you could potentially get 12x FW in Dfish shooting something up, possibly with crossfire etc which would be quite potent. In conjunction with a Crisis assault this would be very deadly.
However, even without this cost reduction the current list is fairly easy to 'popcorn' to reasonable effect eg:-
Hero Cruiser         150
Fire Warriors         200
Fire Warriors        200
Fire Warriors        200
Fire Warriors        200
Scorpionfish + SC    350 (BTS)
Stingray support group  225
Stingray support group  225
Recon support group  150
Recon support group  150
Recon support group  150
Orca dropship        150
Orca dropship        150
Orca dropship        150
Barracuda Fighters   175
Barracuda Fighters   175
Giving you 16 activations with the Cruiser for TK shooting, Scorpionfish and Stingrays with Recon groups for objective grabs and long range shooting, Orcas and FW for local attacks and air cover if needed. Depepending on how you play it, 12-15 activations per turn and the ability to planetfall a nasty surprise.
Or you could drop the fourth FW cadre to upgrade the Stingrays back to HHeads and use the remaining 150 points to convert another FW cadre to be a Battlesuit cadre with upgrades, dropping the army to *only* 15 activations.
(Edited to correct the 'Skyray' error)