Help me find the cannibal!

[Hazarrd]

I just setup a new 60 gallon freshwater tank with no plants. I moved 1 adult angel and 2 adult denison barbs to this tank from an old tank, and they have been in there for approximately 2 weeks. Yesterday, I added the following to the tank:

6 silver hatchets
8 cardinal tetras
8 harlequin rasboras
4 fiddler crabs
4 nerite snails
1 blood redeye swordtail

It is clear that something is eating/destroying the rasboras. I ordered these online, and they were much smaller than I expected. It is also possible that a couple of the tetras have disappeared, but I can't confirm. Any idea who the culprit is? My best guess is the angel, but would like to hear your thoughts, and how certain you are. Would I have better luck if I bought older (i.e. slightly larger) harlequins/tetras, or will the problem persist? I also plan on getting a school of celestial pearl danios. Will I have the same problem?

 

[shellieca]

Thats a lot to add at on time. Have you tested your water for ammonia, nitrites & nitrates since adding them? You could get a mini cycle because of the sudden added bio load. I would start by checking the water parameters, then going from there. It is possible you received some ill fish & they were nibbled on after death. It's possible they were bullied by other fish. Were all of them properly acclimated?

 

[Hazarrd]

Yes to proper acclimation.

 

[sp0ng3r]

The rule of thumb is, if a fish can fit another fish it it's mouth, it will eat it.

How large are your other fish?

Are you sure they are not dying because of disease or something else, then everyone is eating his corpse?

It could be either one if the other fish is big enough. Angels are a possible culprit as they are often aggressive.

 

[delfisherman]

depends on the size of your angel. mines fully grown and i cant have fish smaller than an inch or she will eat them tetras mollys it doesnt matter

 

[Readingexcalibur]

Don't forget that angels are a cichlid and not a tropical fish. They can be aggressive! Just for future reference, you should never add that many fish to tank at one time. You can crash the system, and I am a walking testament to that when I first started keeping tanks so many years ago!

 

[Samzter]

Don't forget that angels are a cichlid and not a tropical fish. They can be aggressive! Just for future reference, you should never add that many fish to tank at one time. You can crash the system, and I am a walking testament to that when I first started keeping tanks so many years ago!

Angelfish are tropical fish?!

 

[Rivercats]

Since the problem arose after shipping fish it wouldn't surprize me if you lost some to the stress of shipping, especially if they were very small. As stated once dead any of the other fish could have munched on them. So have you noticed the lone angel chasing the small rasbora's today? If it is killing them it will be going after them all the time, enough that you would notice. I've been keeping angels for over 30 years and currently have 12 adults in a 220g heavily planted tank that has alot of small fish, and as it happens we added 13 tiny rasboras 2 weeks ago, the smallest being about 3/8" long and the angels don't even look at them. Just as small is a school of very young cardinal tetras in there also. Angels all have different personalities but often get blamed for casualities. Yes the are cichlids and they are in fact tropical fish but they are not always the small fish killers they are often made out to be.

 

[Oceangirl]

fiddler crabs. Stress from the transfer makes them EASY targets. I brought home some cardinals and they did not look happy. I watched a Ghost shrimp pluck one from the water column and begin to eat it. I managed to get it away and returned them, and got neon tetras. They are beautiful! They just got them in and are small, young, bright and look amazing.