My new hare dissapeared two days after I got him. I'll wait a few days to declare him dead, but this is bothering me. I have LOTS of algae, hair and macro, growing in my tank. I have a few theories, let me know what you think:
1) I have a poisonous algae. I have some hair that is brownish-red, I'd read somewhere that some are poisonous? I noticed his poops the second day were bright orange.
2) The flatworms (the velvet nudi's almost elminated them) are getting eaten and poisoning him. This falls in with my bright-orange poop observation.
3) He's coming in contact with the velvet nudi's "slime", (every time he gets caught in a high-flow area he releases some) and it is poisonous.
4) He's sufficating. I think I've got pretty good aeration, and with all that macro algae you'd think oxygen is plentiful. But since the hair algae frequently clogs the overflow slits, the tank occasionally gets filled to where the water it touching the glass, so there's no gas transfer going on at the top of the tank (I still have an open sump with protein skimmer) until I brush out the slits.
5) I have a critter in the live rock that's killing and eating them. I did see a small fish that died in my tank getting lifted up to a hole behind the live rock - though the fish was pretty small, it seemed too big for an amphipod to carry and maneuver like the fish corpse was doing.
6) My tank parameters aren't right for him. The water is generally around 81-82 degrees, 1.025 for sg. There are 0-readings for trites, trates, and ammonia, before someone asks.
7) One or both of these things are actually still alive, but hiding REALLY well, to where my repeated attempts to locate them, day and night (with flashlight) are fruitless. This would also involve them not eating very much, since the hair algae is not going away.
