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Mass Molly Suicide!!!

5K views 19 replies 10 participants last post by  K Road 
#1 ·
I have kept t. fish for over 20 years, have three aquariums and in all these years never had any probs. except last night. I have 60 litre tank in the B.Room. Last night I awoke to the sound fish impacting against the glass... thump, thump, thump. I got up took the lid off and peered down. The black mollies were making frantic (and fatal) impacts with the glass sides of the aquarium.

I went back to bed - there was nothing I could do at 2am. In the morning thirty plus mollies were dead. The night before they took their food as greedily as ever. This is the strangest thing to have happened in all my years as a aquarist.

My theory... Over-populated tank! Mollies release some kind of chemical that produces a mass flight - "I gotta get out of here" - sort of reaction. No where to go in an Aquarium - result mass death by impacting the glass. I fished the dead ones out, did a 50% water change now everything back to normal with the few surviving black mollys and the platies. A few swords were affected as well. Weird and just a little macabre too.

Any one know the cause or has had a similar experience, please?
 
#4 ·
I'm a little torn here, on the one hand I'd like to say sorry for your loss.

But, and mainly, on the other I'm leaning towards my original of wtf. Why would you lie back down and just listen to your fish die? I mean, come on! You've got 3 tanks, and say in your mind overstocked, then why have you let it get to this level for one? I have zero idea how many mollies you can keep in a 60 ltr as I don't like the fish, but with the others you mentioned I'd imagine it's too many, espec as it they would just keep breeding and the situation keep getting worse....
Second.... water change, put your hand in, scare them, shake the tank for god sake......but snap them out of it somehow surely.... just lying there defies belief in my mind.

As I said, I'm sad for the loss, but I'm more shocked and appalled tbh.

Welcome to TFK :roll::roll::roll::roll:
 
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#6 ·
Lets see 60ltr is roughly 16 gallons. You fished out around 30 dead fish which means there was more than 30 in there to begin with cause you said not all died. If I had to live in conditions like that I'd eventually bang my head against a wall to die too.

I'm willing to bet this guy never comes back after reading the comments OR the only reason he does is because I said he wouldn't.
 
#7 ·
Joined sept 2011, no posts until now.
sometimes I wonder if posts like this are legit...
anyone who supposedly has fish for 20 years... would someone like that consistently keep over populated tanks??
something does not smell right here.
 
#8 · (Edited)
There are 3 options here IMO of what is going on...
1. The OP views his/her fish as decor and not pets (60 of them in 16 gallons) and views their deaths as an incovenence (did nothing to help them because it was going on at 2am) to keep from hapening again (how could a tank that was that overpopulated function!?!)
2. The OP is actually a newbie and completely oblivious (unlikely as terminology was used)
3. It is a prank and the OP came up with a terrible story to mess with us

Now, please show us which you are. If you are truely a fishkeeper, we would love to help you with your bizzar issue, but we will need you to be honest about your fishkeeping habbits, fish apperance, and water chemistry. If you are a prankster, admit it, say you're sorry, and we can all move forward. I don't know about everyone else, but if you are enough of an adult to admit you goofed, I would still gladly help you with any of your fish questions and welcome you here.
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#10 ·
My goodness, what an unfriendly response from many of you! Yes, the tank was over-crowded from putting off a required cull - I do not relish throwing fish into boiling water as humane method of reducing numbers. My bad! No I was unable to do a 2am water change because of disturbing others badly in need of their sleep - I didn't anticipate the number of fatalies. Water gets changed every three weeks in my tanks and I regularly receive compliments on the condition of my lants and fish from other aquarists.

So many thanks for the sarcasm and warm welcome my fellow aquarists. You've been most helpful and friendly!
 
#11 · (Edited)
I wasn't being rude, just careful. You have to admit that it's a very bizzar situation. I can understand not wanting to wake other people in the middle of the night. There are a few things I would like to point out though...

A pwc every 3 weeks is not often enough (unless you have a massively planted tank), especially when you are so very overstocked. Stir the gravel and see how much mulm has accumulated in it. It will most likely be very dirty. Up your pwc to every week.

Boiling fish is not humain and is actually very painful. You could rehome the fish by giving some away or uthanize with clove oil or severing the spine. Even the freezing method is a step up from boiling.

Now, what is the current stock in your tank? What's the pH, Hardness, Amonia, Nitraite, and Nitrite. How do the others look (spots, discolorations, behavior...)? Is there an odor (rotton egg, fishy...)? Were any chemicals used in the same room as it (air freshener, flee powder, cleaner)?
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#12 · (Edited)
Can't believe any person with 20 yrs expierience would let scenario described develop .
Whole thing sound's fishy to me (excuse the pun).:roll:
In any event ,the fish most assuredly did not commit suicide, but rather were most likely poisoned by their own waste and or excess decaying foods,plant matter, which in small tank's that are over stocked,no weekly water changes, build's quickly.(ammonia,nitrites)
With number's of fish mentioned,weekly or perhap's twice weekly water changes would have averted this disaster.
 
#13 ·
I don't know, maybe my initial post was a little harsh. Maybe not.
You did decide to post it on a discussion and opinion forum though, and you can't expect positives all the time, especially in situations like this. We're not here to pat your head and praise you.....

Moving on though, I think seeing as though you do have survivors and the situation of stocking will come up again, you should start looking NOW at where to outlay them. If you can't sell them dirt cheap.... go and see your lfs. You can either donate them for free just for the good of your fish Or most will offer you small bits of credit.... for instance they will keep your fish fed whilst you continue to resupply them with fish.

Secondly I'd definitely agree with the others.... up your maintenance schedule and clean ALL your tanks weekly. Every 3 weeks is way to long.

This has at least I'd imagine given you a shock to the system and hopefully will change your fish keeping practises for th better.
 
#14 ·
You stated "others" plural needed their sleep, which makes me think you might have young ones in the house. Could something have been added to the tank without you knowing? A child giving the fishies some of their drink or food? I know this is a very common occurrence.

I can understand the idea of culling fry seems horrible, but as aquarist we must sometimes do this. Do call around to the fish stores in your area and see if they will take the babies and make sure you know how big they need to be for them to do this. Even if you get nothing for them, at least you won't have to go through the pain of culling or events that just took place in the future. Contact local elementary or child care centers to see if they want/need fish for their classrooms. Many forums have places where you can post "for sale" threads, classifieds, sell them or give them away.

I admittedly am new to the hobby, but the idea of mass suicide seems over the top, sounds more like something was in the water that poisoned the fish. I do hope you can use some of the suggestions to help you with managing your fish population in the future.

Good Luck.
 
#15 ·
I appreciate the less hostile tone... I posted because, as stated in the OP, this is the strangest (and most grotesque) event I have ever experienced in twenty years. At first I thought maybe there had to be something in the food (fresh German Vipan flake) but the other Aquariums are fine. Ammonia spike is unlikely given density of plants and the fact that you see changes in behaviour when chemical imbalance is developing before it reaches critical mass so to speak. There was the usual feeding frenzy just hours prior to this event, and no I did not over-feed. Yes, I admit it was an overpopulated tank due to my reluctance to cull. (BTW: My books do suggest the boiling water method - cruel and repugnant though it may sound) The filter had "matured" and was working fine and strong.

I posted because this seemed like an attack of mass hysteria - only among the black mollies - the swords and platies were unaffected.

I have no concrete explanation! As I suggested earlier, perhaps it was a chemical release from the mollies as a consequence of over-poulation with a chain reaction from the other mollies once they picked up on it which in turn triggered off a flight response mechanism - but - with nowhere to go but the glass - bang, followed by an obviously quick death from the impact.

However, I have learned of the necessity to cull and unpleasant though this is, it will be the way of the future. It has been a most unpleasant episode for the fish and myself.
 
#16 ·
Change in behaivor was there,,fishes trying to leave the toxic condition's brought on by over stocked tank, and no one knows what water parameter's were/are.
Fotunate all fish were not lost.
 
#17 · (Edited)
I understand you have a planted and cycled tank, but they can still get out of wack. Is there any way you can test the water perimeters?

I also understand that many of the older books speak of boiling as a way to euthanize, but that method is no longer supported by the FDA or any organization. In fact, it has been shown to induce immediate temprature shock with cold water fish, not tropical! You can imagine the repercussions of this.

The methods that are most used now are snapping neck, severing the spine, clove oil, and anestesia OD. It is also acceptable to cull fry by feeding them to another pet. Now if you want to continue the boiling method because it works for you, that is your decision. I'm not about to judge. I just wanted you to know how much has changed.

Which reminds me, how long has it been since you did any research on fishkeeping. So much has changed in the last 20 years and there have been breakthoughs in the short time since I started!
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#18 ·
I'll enter this thread at this point. And first, K Road, please understand that the explosive reaction in the first posts were because these members really do care about fish. Circumstances between members obviously vary, and we are not all able to do this or that, but we share a real passion for fish and hate to see suffering on the part of any one's fish. When this is the case, many of us can easily over-react. Please understand, and let's move on to the solution.

Which unquestionable involves re-homing some of the fish. A 60 liter or 15 gallon tank is insufficient space for any but a couple livebearers whether common molly, platy or swordtail. Were/are these fish fry perhaps? We have fish profiles, clicked the shaded name for the profile which has minimum tank sizes, numbers of fish, etc for that species.

The improvement after a 50% water change shows why regular water changes are so crucial. And the more fish the more essential. At least once a week, changing 1/3 to 1/2 of the tank volume, if stocking is balanced to the tank. More frequent changes are necessary if fish stocking is beyond that balanced in the tank.

But we still need the numbers for the tank water. Ammonia, nitrite and nitrate. Also, GH and pH. Livebearers are hard water fish, and they are especially susceptible to ammonia poisoning.

Byron.
 
#19 ·
After some pondering last night,and cooler head this A.M.,I think I might be able to help shed some light on possible comtributing factor's to fishes demise other than the obvious overstocking issues although it must come into play.
Many folk's are often told here,and on other forum's ,that heavily planted tank's will allow foregoing the cycling period for plant's will quickly assimilate the ammonia produced by fish as by product of respiration, and this is true so long as plant mass is more than the fish load ,fish waste,fish food,created in glass box of water on daily basis.(cycled,or uncycled aquarium's)
Problem lies with what I or you, may consider heavily planted.This is subjective, like water parameter's being described as good,normal,fine,etc.
Also remember that plant's produce oxygen during the day during photosenthizing, but in the evening when light's are off (as they should be), these same plant's use up quite a bit of oxygen and in crowded tank,,the oxygen level's can get dangerously low.(too many fish for available oxygen)
This may have triggered the beginning of the end for the fish lost.
Certainly possible that thirty dead fish (about twenty too many in 60 Litres) could have resulted in ammonia /nitrites climbing fairly quickly in a few hours time.
Add low oxygen level's for number's of fish ,,and scenario described would not in my view be surprising.
Other's who place fish tank's in bed room's often find the noise from bubbler's,filter's,hamper's their sleep so they turn off the filter's, air pump's and in crowded tank's fishes quickly feel the effect's.
Still other's kill off fish with miss- application of CO2 which often happen's during the evening when too much CO2 and not enough oxygen exist's for the number of fishes present in a relatively small volume of water.
WeeklyWater hanges are the fishes friend in glass box of water where there are no tides,current',rain's,to wash pollutant's away.is of paramount importance in over stocked tank's plant's,or no plant's.
 
#20 ·
Many thanks for the helpful replies. They are most appreciated. I will buy a testing kit this weekend, as the paper strips I have are very unreliable, though I'm sure in view of what happened even these would have indicated serious problems in the chemical balance. Yes, the reference books I possess are indeed twenty years (plus) old ... evidently long outdated in light of current research and equipment. I will (reluctantly) cull on a regular basis - mercy killing is preferable to suicide. Rate of partial water exchanges will be increased and I will bear in mind just how quickly a siuation can go from being apparently normal to tragic.
 
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