which mage pet to use in a necro mage duo

[Velerin]

If your pet isn't tanking I think the water will do better dps-wise. Multi-pet tanking is kinda screwy. Its hard to spread out who's consistently tanking. Best way is to periodically pull back and re-engage to spread out damage. But with a necro usually best to just fear kite with 2 pets banging away.
For fire pet to be most effective you need to be targeting single low con blues which usually isn't what you want to target when you have a powerful duo like that.