One Dead Fish

After a year of having my tank my first fish just died. I have a 75 gallon tank with 8 Green Tiger Barbs, 4 Cherry Barbs, 3 platys, a guppy, and a Rainbow Shark. I just noticed a half eaten Tiger Barb at the bottom of my tank. I don't think it was a victI'm of a fight due to the Tigers being the the most aggressive and the biggest in my tank. I guess the Rainbow could have gotten to him, but I think it's a far chance. Also, the most important thing to note - I noticed one Green Tiger's color was fading a week ago. I kept an eye on him, but he wasn't acting out of the ordinary. I didn't notice any change in any other fish's color. Just came home from work and noticed the other fish were picking at the dead fish.

That faded tiger is the one that has died (I'm assuming). What should I do in this situation? I tested the water and everything but the pH is normal. The pH had gone up only a little bit, but nothing significant at all. I'm about to do a water change. Any ideas what the cause of death could be?

Orginally I had 5 Green Tigers and about a week and a half ago I introduced 3 regular Tigers. The 5 Green are much bigger than the newly introduced regular tigers. Could it have been stress related due to new fish in the school?

 

I would test your kh, as that could be the reason for the ph shift. You could have possibly had a ph swing, which will kill your fish. I'm afraid if there's a larger PH swing more fish could fall ill

 

What does kh stand for?

I added salt to my house water about a month ago. Could that have done something drastic?

 

Kh is like alkalinity. It's what buffers your ph so you don't have huge swings. And it depends on how much salt it is. A small amount could be harmless

 

What did you actually test for and what were the results? I'm guessing that you didn't test for Nitrates.

Have you done regular maintenance on this tank? Explain.

You say you added salt to your house water. Is that for a water softener system or did you actually add it to you aquarium water. What kind of salt was it?

Aquarium salt is safe for most fish at the recommended doses but the regular use of it is up for debate. The reasons for and against its use are not so clear. Anything you see about it being bad to use at all or saying it should be used all of the time should be ignored.

 

Sorry for being vague. I tested pH, high pH, amonia, nitrite, and nitrates. All are at what they're supposed to be at, aside from the .3ish spike in pH

Added salt to my house water to soften. Although, that is something I always have been doing

 

You're still being vague. What were the values that you measured? They are supposed to be zero. Nitrates are hard to keep at zero, that's why we do water changes. If ammonia and nitrites showed anything more than zero, it could be an indication of something going on with your cycle. Please post actual values. Some kits will tell you that low levels are "safe". They might be non-toxic but can still be indicators that your cycle might be going awry.

 

pH-7.5, ammonia and nitrate were 0, high pH - 7.4, and nitrite 30ppm. These have been consistant since I established the tank over a year ago aside from the tiny jump in pH

I do water changes/vacuum every week and a half or so

 

I assume you meant the Nitrates were 30ppm, not the Nitrites.

Rainbow sharks can be very aggressive and it can happen after the lights go off. I would keep them in a trio at a minimum. That way the aggression will be kept to the group, similar to Tiger Barbs, and not be directed towards other fish.

 

Correct, nitrate at 30ppm not nitrite

Interesting. When I was researching into all of this I was told to keep only 1 Rainbow in the tank. I find it surprising that it got to one of my tigers when they are similar in size. Thanks for the help

 

It's just a guess that it was the shark. It could very well have been a weak fish that got picked on by the others.

Rainbows are aggressive amongst themselves but groups will spread out the aggression, so that you don't get one that is picked on constantly. I just did a quick search to make sure I give you good advice and a couple of sites recommended groups of six. Not a bad idea for your 75. The dominant ones will color up very nicely with competition around. Three would be the minimum but not guaranteed to work.

 

He's getting fairly big. I'll pick up 2 more Rainbows.

Although I'm still very suprised at a Rainbow attack on a large Green Tiger that's schooling. I feel as though the Rainbow would have gone after my lone guppy or even the platys

edit: I'm also noticing the Tigers becoming aggressive towards each other, maybe to show dominance. It's just odd that they start this a year after in the tank

 

Keep a close eye on them. If you lose one, it's fairly certain another one will follow. Three is the bare minimum, if it works. Personally, I like the fish and would go for six in a 75.

 

You're talking about the sharks right? I feel more than 3 sharks they would dominate all the fish

 

Yes, the sharks. They would definitely be prominent in the tank but not really dominant as the aggression is directed towards each other and not the other fish. They not only show their colors nicely in groups but they are extremely active because of their aggression towards each other. Really fun to watch.

 

Will do. I have a black with red tip Rainbow, but I remember seeing them come in a different color at the store. I think grey/blue? Will they work just the same?

 

As far as I know, unless you are referring to albinos, if they are a different color they are a different species and probably won't behave the same as if you had all the same. Albinos probably wouldn't mix with normals of most species, either.

 

I've learned a lot. Thank you for your help