Find the killer fish...

[eparadis]

Ok, so someone in my tank (55 gal, planted, 40w, C02, HOB filter) does not get along well with others. I have a small clue as to whom is the killer, but Professor Mustard was not in the Aquarium with the algae scraper, so I am a little befuddled.

Current cast of characters:

1 Pleco - about 6 inches long. Nice dorsal fin.

1 Cory Cat - albino, he just hangs around scavaging what he can.

1 Clown loach - I had a snail problem when I planted the tank. He is about 3 inches long, great colors. Lives in and under my little plastic decaying castle. Tends to be in one of the towers upside down playing with the air bubbles. Misses his buddy.

1 white balloon Mollie - very lonely now.

4 Swordtails (Marigold and Blood red). 3 female, one male. Random amount of fry. Right now there seem to be about 4 that are close to 1/2 inch.

The Missing....
Clown loach, smaller than the surviving one.
White balloon Molly. Found this one stuck to the intake with some chunks missing.
Swordtails - My original male was killed shortly after my current male got a wee bit bigger. Sounds like a motive. Then there were about 3 babies that got big enough to be noticed and killed.
Cardinals - a whole freakin' school. Dang. About 2 per day for a week. I did not have anywhere else to put them and I thought it might have been a water problem and did some good changes, but now I think there may have been foul play....

I do not think it is a water problem. It may be. I do 50% changes every two weeks with dechlorinated tap water. San Francisco water is pretty good for the fishies I found out. I have an Algon pouch in the tank to combat nitrates and slow down black beard algae, which it has done.

So, to make a short post even longer.....

Who is the killer?

 

[fishfreek]

Do you test your water for ammonia?

Many of the fish you list will prey on a dead fish and take chunks out or even devoure the entire fish minus the bones. Sometimes people confuse this as being the cause of death vs something that happens due to the death.

Kinf of like seeing a vulcher around a dead animals all the time might lead one to deduce that it was the vulcher that killed it.

 

[eparadis]

Would bad water be so random though? I can see it for the Cardinals, but why not have problems with all the swords, or mollies..... :?

 

[fishfreek]

Does everyone in your house get sick when 1 member of the house does?

Probably not.

the weaker fish of a given species will come down with symptoms first while others who are stronger might not show such signs until conditions worse or prolong.

Testing your water is critical when trying to determin whats going on with your tank.

 

[eparadis]

Good analogy thanks. What is the best complete water test kit to use? I have terrible flashbacks to high school chemistry when I think about controlling the water better.

 

[Catalina]

Aquarium Pharmaceuticals makes a good complete test kit for PH, nitrites, ammonia, GH, and KH. It is what I have. It does not include a nitrates test, but I think it is most important that you test for ammonia and nitrites, since it sounds like that might be the problem. How long has your tank been up?

 

[eparadis]

Tank has been up for over a year. Pleco is about 3 years old, he moved from my frog tank to this when I built it. The adult survivors that I have are all about a year old give or take a month or two.

 

[eparadis]

Ok, test result are in....

0 Nitrates, 0 Ammonia, Ph is at 7.2. Temp is at 78F, at the far end of the tank, at the top, away from the light. Did not get a GH or KH test yet.

 

[fishfreek]

Is that NitrAtes or NitrItes ?

There is a difference in that NitrItes are toxic like ammonia where as NitrAtes are less of a concern.

My guess is you ment to type NitrItes because your established tank has a reading of 0 and its very unique to have an established freshwater tank with 0 NitrAtes

 

[eparadis]

Thanks for the correction, you are correct. Big difference.

0 Nitrites is what it should have read. Getting a GH and KH kit today.

2 people thought the Pleco did it? I didn't think that they were aggressive.

 

[fishfreek]

The pleco would most definatly take a chunk out of a dead fish. (at least thats my understanding)

 

[eparadis]

That makes sense, but I doubt the Pleco actively killed anyone.

Further water tests - 0 Nitrates as well, KH and GH were around 150 ppm.

 

[echo7]

i think the male sword could have killed the other one, but thats the only murder i could see happening. maybe if there was a nocturnal crab or something that came in on plants- could such an animal hide in your tank during the day? were there any signs of disease on any fish?

 

[TheNewGuy]

Just a thought but your BIO load doesn't look like it's high enough to need a 50% water change every 2 weeks you may want to cut that back to 25% once a month. Also what kind of plants do you have in your tank and are you using any fertilizers? What kind of filter are you using, how often are you changing the filter medias? I think that should keep you busy for the moment.

 

[ghettorigged]

I would have to go with water quality here. None of the remaining fish seem to be known for aggressive behavior. :?

I can't point any fingers though because I have enough algae to kill any tank. Don't keep the lights on, get brown plants. Keep the lights on, get algae. Don't feed the angels what they want, have missing tetras. Feed the angels, encourage the algae. {sigh}