I think.... What most of us are forgetting... Is Arctovosh’s perfect 55 base speed!
Arctovish @ Lagging Tail
Ability: Water Absorb
EVs: 100 HP / 252 Atk / 96 Def / 60 SpD
- Fishious Rend
- Psychic Fangs
- Icicle Crash
The point of its base 55 speed + lagging tail is so that during trick room, it can out speed Hatterene. Hatterene has base 29 whilst lagging tail + 55 = 27.5, slower than the Hatterene, making it a perfect mon in Trick Room, not to mention it out speeding Rhyperior and Tyranitar in Trick a room, only falling behind Dusclops by a mere 2.5 BP.
From here, using the same concept as Dracovish, it can dish out 170 BP Fishious Rend + STAB. (If it’s in the rain, it would be even better!)
252+ Atk Arctovish Fishious Rend (170 BP) vs. 0 HP / 0 Def Cinderace: 314-372 (202.5 - 240%) -- guaranteed OHKO
252+ Atk Arctovish Fishious Rend (170 BP) vs. 176 HP / 4 Def Solid Rock Rhyperior: 300-354 (141.5 - 166.9%) -- guaranteed OHKO
252+ Atk Arctovish Fishious Rend (170 BP) vs. 176 HP / 4 Def Solid Rock Dynamax Rhyperior in Rain: 450-531 (106.1 - 125.2%) -- guaranteed OHKO
252+ Atk Arctovish Fishious Rend (170 BP) vs. 0 HP / 0 Def Dynamax Tyranitar in Rain: 344-408 (98.2 - 116.5%) -- 87.5% chance to OHKO
Though I have to admit that Dracovish is a MUCH better Fishious Rend spammer, Arctovish shouldn’t be sleeped on in a rain + trick room team. Combining it with its ability water absorb + Surf, it becomes a deadly threat to a lot of teams.
In conclusion, good mon for trick room. However, not the best in general but still shouldn’t be sleeped on.