Unknown cause of death

[Genera]

I've had two male sailfin mollies for about a week now and I purchased 4 females yesterday. They all looked good and healthy but one had some torn fins (fin rot?) so I acclimated them to saltwater over 8 hours which worked well with the two males. I didn't have the option of QT at the time but there would be no marine ich, brooklynella, or amyloodinium because they were originally in freshwater and those parasites cannot survive in that environment. So I turned off the lights of overnight and after an hour after the lights on in the morning the molly with the tattered fins was hiding in a corner and not moving much . I turned the lights off for 8 more hours and when I turned the lights on the tattered finned molly is stuck to the overflow/intake but still breathing so I immediately released the fish and then all activity stops. So now I'm left with a dead molly. I just fed the remaining 5 mollies an algae wafer and they had a piranha feeding frenzy. Any idea why she died? The only symptoms visible were hiding in a corner, weakness, and tattered fins.

Parameters-
Temp- 79F
SG- 1.025
Ammonia- 0
Nitrite- 0
Nitrate- very close to 0
pH- 8.3
dKH- 8
Ca- 425
Mg- 1250

These pictures were after I had extended the fins and tattered them more, the original state of the fins looked like this but on the edges. Good quality camera is in the repair shop.

Caudal Fin

Dorsal and Caudal Fin

Full Body

 

[Dkuhlmann]

It was probably sick before you acclimated it to saltwater and it was too much for it. Who knows

 

[Genera]

Yeah, the other 5 are doing well at the moment. Hope no more of them take a turn for the worse.

 

[o2manyfish]

Bought a fish that wasn't in perfect condition, then took an unhealthy fish and put it through a major transition in all of 8 hours and now your asking why did it die????

You're dealing with a living commodity and non-perfect conditions.

 

[Genera]

Bought a fish that wasn't in perfect condition, then took an unhealthy fish and put it through a major transition in all of 8 hours and now your asking why did it die????

You're dealing with a living commodity and non-perfect conditions.

In reality, I didn't notice the tattered fins or poor health at all at the time of purchase and this transition worked extremely well for the first two mollies I got. (When I purchase fish, I observe them for a while, check their state of health, and ask the LFS peeps to feed the fish a small amount). When I noticed the one female with the ripped fins I tested the leftover bag water and got a reading of .22ppm ammonia, will be notifying the LFS about this. Where they live in the wild, they switch salinity changes fairly rapidly, swim down to where the river meets saltwater, then swim on through. I'll definitely quarantine any new fish from now on. Even if I don't have a QT tank or supplies at the time, I'll go get some. In all of my previous tanks (except for my first one where I made EVERY rookie mistake in the books) over the 9 years I've been in this hobby I've quarantined and had no losses of disease, but had to rehome all of my fish/inverts and sell all my supplies and tanks due to family complications.

 

[Martini5788]

Did the male mollies chase the females around? They get.... Not sure how to say this haha.... Excited... Very excited... When females are around. Male mollies have been known to chase females to their death attempting to mate with them. So I think it was probably a combo of acclimation issues, being chased around.

 

[Dkuhlmann]

Martini5788 very good thought on this. All mollies and guppies do is breed

 

[Martini5788]

Martini5788 very good thought on this. All mollies and guppies do is breed

Thanks. The males really are relentless, crazy lunatics.

 

[Genera]

The males really are relentless, crazy lunatics.

That probably was another contributing factor. The two males I have swim around and chase each other off from the females as well as chasing the females trying to mate with them even after they are mated with, probably need to get more females to separate the males' aggression even more. Mollies establish a hierarchy, and if you have enough females, the more 'powerful' males with turn their attention to each and every female so less and less chasing the more females there are. I have a batch of females that I've been QTing for a about a month now and don't seem to be showing any problems. A few days ago I just had to put some in from the LFS so the males don't beat each other to death. Will probably be releasing the females from QT within this week.