Internal bleeding - is it contagious?

[geneticmaize]

We have a Danio that is smaller than our other Danios that has been swimming strangely for 2 days, trembling and mostly staying in one spot. This morning I noticed what seems to be internal bleeding on one side, toward the tail. It rapidly got worse this morning, so I just euthanized it with ice. RIP little Danio.

So my question is - is this contagious vs some sort of genetic deformity or maybe one of the other fish hurt it? If contagious, what can I do to treat the other fish? I was thinking to replace about 20% of the water tonight.

Background - we have 4 Danio in a new 20 gallon tank (also a gold mystery snail and some moss balls). They seemed to be getting along fine, and the others are all swimming around and eating as expected. I am totally new to this, so I may have gotten the fish too soon. The tank has been set up for about a week, but I had added bottled bacteria along with the water conditioner. It was set up for 2 days, then we got 2 fish, then two days, then 2 more fish. There's a regular filter, and I added a sponge filter with airstone last night.

My pH is about 7.4, ammonia is about 0.25, nitrite is 0, nitrate between 0 and 5. I'm going to PetSmart later to have them test the water, too.

 

[geneticmaize]

Petsmart used test strips so probably not super accurate but all the measurements were where they should be. So it's probably not a water chemistry issue.

I did notice that our other 3 Danios have a little reddish gills but looking at photos of Danios and specifically glofish Danios online it seems many of them do have reddish gills naturally. Otherwise they look healthy and are all zooming around as expected.

I'm not sure if I mentioned before - these guys are all glofish, which supports the idea that the fishie was just inbred and genetically unhealthy (thus hopefully not contagious!). The deceased one was orange, and we have a purple, blue, and red remaining. When I went to Petsmart today, I noticed that all the oranges were smaller, so not sure if that's an age issue or if they are just smaller.

 

[Delapool]

I’m guessing it’s the new tank as tank cycles / slightly high ammonia to give a water chemistry issue. Rather than parasites which could also give the same effect.

I’d go for water changes and monitor them. Ammonia burns can take up to three days to show so would keep testing.

 

[fishwonder]

You say you have a new 20 gallon tank. A week is not enough to cycle your tank/filter as this takes about 3-8 weeks to complete before any fish should be added.

Here is information on how to cycle your tank/filter.

 

[geneticmaize]

Ammonia and other chemistry tests are all where they should be. I now know we should have waited longer to cycle but of course no one tells you this when you get a new tank and I didn't start researching in earnest until we already had a few fish.

I just had to euthanize a second glo danio... I think one of the remaining fish is a bully and bit this one and the previous one that died. Both had internal bleeding, the first one near the tail and this one in the belly. And this one actually bled externally a little, I think the injury broke the skin.

So there are 2 glo danio left. I am inclined to go get 3 or 4 regular pearl danio to make a school of 5 or 6. Hopefully stopping the bullying. It's either that or let the bully kill the other one, which doesn't seem acceptable to me.

 

[geneticmaize]

Saw some discussions suggesting to move the aggressor to another tank, introduce more fish to the school, then add the aggressor back in as the new fish, which could stop their aggressive behavior. Seems like a good plan... anyone have experience with this?

I should add - just based on body shape, the first victim was a smaller male. The aggressor, the one in the tank now, and the one that died today are all female. The aggressor is largest and does tend to zoom after the others, who stay low among the fake plants.

Maybe I should just return the aggressor?

But this all assumes these poor fish were bitten, and it's not some contagious disease.

 

[fishwonder]

Since your tank is not cycled, returning the fish would be best until it is. Do not add anymore fish please.

Otherwise try performing a Fish-in-Cycle.

What are your water parameters when you test them with your test kit? pH, ammonia, nitrite and nitrate now?

 

[geneticmaize]

As I stated above: "My pH is about 7.4, ammonia is about 0.25, nitrite is 0, nitrate between 0 and 5." Petsmart tested with strips and found ammonia 0, nitrate less than 20, nitrite 0, hardness 150, chlorine 0, alkalinity 40, pH 7.4.

If I could go back in time, sure I would wait longer before getting fish. Given my numbers, the bacteria in a bottle worked well enough. Now, I need to keep the 2 that are left and keep them alive. My six year old is already devastated that 2 died and I haven't even told her what I think happened.