I have a 55 gallon tank with
- (formerly) 4 angelfish (two inches)
- 1 black ghost knife fish (five inches)
- 4 German Blue Rams
- 1 Random betta that I rescued on a whim

Tonight, my beloved black lace angelfish turned up dead (he's seriously the only reason I got into angelfish. He was the only black lace at my LFS and the guy said angelfish prefer schools so I bought three of the "assorted angelfish".) after no warning. He had been acting completely normal, the exact same way that he acted every day for the 6 months that I had him.

I can't be too depressed over his death, there isn't much I can do about it now. My biggest problem is my other fish. None of the other fish died, and none of them are acting strangely. BUT, considering he was perfectly fine and suddenly died, this isn't too reassuring.

Here are the only two things that have changed in that tank in the past week:
- I added two German Blue Rams, after they were quarantined in a seperate tank for two weeks
- I started feeding TetraColor granules for the rams, and of course the angels nommed most of them anyway.

Can anyone help me figure out what happened to him and help me keep the same thing from happening to my other fish (especially my baby knife D: I'd literally bawl my eyes out if that fish died. He's my baby)

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5 gallon: violet male veiltail betta
5 gallon: platinum male delta betta
20 gallon: turquoise male halfmoon betta, five harlequin rasboras, four otos
20 gallon: red and black crown tail male betta, halfmoon doubletail male betta (on the other side of a divider, of course)
55 gallon: baby black ghost knife fish, two angelfish, three German Blue Rams, five black neon tetras, five glowlight tetras

A few ideas: First, has he been eating normally? Maybe he just stopped eating, and starved.

The more likely option: I too keep German Blue Rams, with angels and Kribs. The Rams paired up, and went NUTS. Killed the Kribs, who were actually TWICE the size. Didn't actually hurt them, meaning there was no cuts, rips or shreds, just harassed to death. Both the male, and female.

Immediately, I pulled out the angels and moved them to my Guppy breeder tank for now. Just my experience.

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120 Gal. Reef tank coming this june. This is going to be awesome.

What are your water parameters? What are your normal maintenance practices?

The parameters are at their normal levels. The water is slightly acidic, ammonia and nitrite are 0.0, and I don't have a hardness tester or a nitrate tester (but my local water is generally rather hard since it comes from aquifers). The temperature is at a constant 80 degrees (although the temperature outside spiked this weekend and we didn't turn our air on until it was already pretty hot, so it may have gotten a little warmer but I highly doubt it)

For normal maintenance, I change 20% of the water weekly by syphoning the gravel. I also scrub the sides of the tank since they are always covered in algae, and that's really about it.

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5 gallon: violet male veiltail betta
5 gallon: platinum male delta betta
20 gallon: turquoise male halfmoon betta, five harlequin rasboras, four otos
20 gallon: red and black crown tail male betta, halfmoon doubletail male betta (on the other side of a divider, of course)
55 gallon: baby black ghost knife fish, two angelfish, three German Blue Rams, five black neon tetras, five glowlight tetras

i dont have a ghost knife either but i to would bawl my eyes out, i love them so much and want one, but anyway maybe he wasnt getting enough food and starved or maybe the rams were picking on it like fishteen said...also the water perimeters coulda been bad...

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Current Tanks:
90G,30G,10G,10G,5G,38G,20G

Once good thing, all else seems ok in your tank. Sometimes individuals of all species, including ours as we know, just die of various reasons. That being said, it bears watching closely right now for sure.

If there were no injuries you could see, did you observe any aggressiv behaviorur in your tank? In my 60g Rainbow tank, you'd think everybody had gone to anger management school. No aggression that I could see. Until I started working the second shift. (only for a week, thank God)

A couple of nights ago, I came home about midnight. I just sat in my den with almost no lights on in the room and watched the tank. A bunch, and a random bunch at that, started doing the Rainbow circle dance.

The Australian would get up next to the New Guinea and they would twirl around, dart away, then some other pair, always a differentrent species and start doing that. I know that's just the way Rainbows fight,(if you can call it that) harmless almost always, but they never do that during the day. My point is that maybe the Rams decided to act in a different way from what you see during your normal observations times. Frankly, I doubt it.

I have seen big Angels get aggressive to each other but NEVER when just a pair. My buddy who breeds them says that any two, similiar sized Angles will get along, regardless of sex. Two females, no problem, two males, no problem, a male and a female, no problem, but three? Often a fight, sometimes to the death.

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60g tall, all artificial plants, Rainbow tank; 55g for African Cichlids. 20g long for fry; 20g hex, 2 black Angels at my desk; 10g planted, with 50 Molly fry; 10 gal, 2x 13w cfl lightning, planted; 2g hex for "Buddy the Betta"; Wanting a 200g +, MTS getting bad.