Need To Know what is killing my fish

[Bocray]

I have had some major problems keeping fish alive. I bought the tank 6 months old stocked with a raccoon butterfly fish a couple of tobies a 6 inch snow flake eel 2 marbled shrimp 2 coral banded shrimp and one mystery shrimp ( THE UN IDENTIFIED SHRIMP IS NOT A MANTIS). They were all killed by ich carpet surfing or predition by the eel .Except the mystery shrimp, and the 2 coral banded shrimp. I then tried some 5 blue green chromis. I lost one of the blues which I thought had escaped from one of the holes in my hood. The next day one of them was missing his tail. I removed the most likely suspect, a hitch hiker crab that burrowed in the sand when frightened. The next day another was missing and the amputee fish had died in the hospital tank. One of the coral banded shrimp had a huge chunk of fish in his mouth.
Tank Parameters
Size: 55 gallons
Filtration: wet dry trickle filter and about 25 pounds of LR
Water Parameters
Nitrate 0
Nitrite 0
Ammonia 0
PH 8.4
Salinity 1.25

I looked around and these seem like perfect water parameters
This is my first saltwater tank
I am feeding frozen brine shrimp
half the tank has a normal hood the other half is egg crate
I ordered a bak pak skimmer which should arrive within the next three days
their are a few pieces of lava rock in the tank but have been there since the beginning of the time I had the tank.
all my invertebrates do fine but my fish die....
PLEASE HELP
EDIT: I do a 1 cup water change every day

 

[mr_X]

you have an eel in the tank and the most likely suspect is a crab? eels are predators. they will eat fish and inverts. my money is on the eel.
a 1 cup water change is not doing much good. you need to do something like 15-20% at a time, and that time should be every week or two.

 

[Kurt_Nelson]

you have an eel in the tank and the most likely suspect is a crab? ...

That kind of sums up my response, also. I think you're just seeing nature run it's course.

 

[David S]

Agree with Mr X,plus brine shrimp isn't meaty enough for the eel.

 

[iDream]

yeah, all those fish are easy targets, you definitely shouldve expected the chromis to die by the eels hand, or mouth.

though its small it'll try to eat just about anything, the coral banded was probably munching on leftovers of the eel, they arent too tidy

 

[Bocray]

They were all killed by ich carpet surfing or predition by the eel .Except the mystery shrimp, and the 2 coral banded shrimp.

I appreciate your responses however I believe you miss understood the question. The eel was dead long before the cromis got put in the tank. So I doubt the eel is the problem
Any Other Ideas?

 

[David S]

Ah.
I would then try to catch the crab with food in a glass trick then photo it and put it in your sump.

 

[cmor1701d]

I agree on catching the crab.
Start doing some 30% water changes every week, then cut back to 10%/week or 20% every other week. Top off the tank daily with RODI water (which should also be used for the PWCs).

I hope you mistyped and the SG is really 1.025. Are you using a refractometer to check it?

Also lava rock may contain heavy metals. It would be best to replace it with coral rock.

 

[Bocray]

I removed the most likely suspect, a hitch hiker crab that burrowed in the sand when frightened. The next day another was missing and the amputee fish had died in the hospital tank. One of the coral banded shrimp had a huge chunk of fish in his mouth.

Thank You for the responses
I will increase my water change frequency and remove the lava rock
However the hitch hiker crab was removed after the second death
Any other ideas on who killed my fish?

EDIT: yes 1.25 was a typo and I am using a refractometer