Australia's Science Forum

Yesterday they were fine... swimming around looking happy .. if fish can smile they were...
Today 8 of them are dead, died, kaput, finito!!!!!

I would be asking a lot of questions, sounds a little sus to me,
It is very sad for you, hope your day gets better
Lisa

Water quality. Something had been introduced if they were fine and active yesterday but are mostly dead today. In a science lab it could be a multitude of things from soap/acids/bases to copper sulfate/potassium perm. - all bad for fish. If the dead fish have their mouths agape, they died stressed - a sign of poisoning or low dissolved oxygen content. If they died suddenly they will still have a slimyness to their scales which is vital in healthy fish. Any fin rot (sign of overfeeding) or milky membrane covering the fish? Both are bacterial but not sudden killers like you have mentioned.

If some are still alive do a slow 50/50 water change now and another every 2 days for a week. Add water ager if you can if using mains water. Never use distilled water in an aquarium. A thorough gravel clean will be in order too along with any rocks etc.

aww mushroom.
Any clues?
I had a few students think it would be great fun to add dry ice to the aqaurium.
Found them all the next morning, dead as if in suspended animation.

Mushroom, sorry to hear about the fishies.

We have a sign on my tank that shows Bruce from Finding Nemo, with a speech bubble that says "Fish are friends, NOT TOYS" Then I made the roughest, toughest child in Yr12 personally responsible for the health and well-being of the fish. Worked a charm! Pity she graduated. (on one plane at any rate).

Meanwhile, did you do any post-mortem water testing? pH is a good place to start.

The fish look like they have been dead for days! Their scales are falling off and their bodies are disintegrating- that just doesn't happen overnight! I reckon one of my little darlings thought they would add something extra to the water!
I have removed the still alive ones and put them into an isolation tank... this afternoon after all the precious ones leave I will be emptying, cleaning...sigh...
I know I know - Some mothers Do have 'em!

The other fish will start to eat them almost straight away hence the look like they've been dead a while.

Regular water changes are a must (especially in schools) and pH will never be a problem if done once a week. This along with only as much food as they'll eat in 3-4 minutes once a day and activated carbon in your filter will have a healthy clear aquarium all year round.

Now if we can just keep the little mongrels (students) from 'adding' things to the water all will be fine.

AHA! the pH of the water is 3 !!!!
No wonder my poor little things died...
As no classes in that room yesterday did any pracs with chemicals, what would it take to change neutral water to this pH ina 3ft tank??

A water change about 2 years ago! pH3 - they would have been doing it tough for some time. 7 - 7.3 is ideal. Even packed with fish it would take weeks to get to that level.

Do you feed them blood worms? That can accelerate the pH dropping quicker than otherwise.

certainly not down to 3!
Thats stomach acid !

Sabbotage?
Childish pranks?
Can you track down to when the last class int hat lab used any acid? or anything? Was the water cloudy/coloured at all?

I have just set up another tank in the bio room .
Students brought in 3 bags of fish as a present for the teacher..straight from the pet shop.. but at 2.30 pm.

We had no warning, so you can imagine the flurry I had to try set up a whole bang aquarium at the end of the day. Scraping together spare gravel, rocks filters etc. Phew

Newbies are doing well.

I DO hope that you've managed to save a few at least.

Please give them a big kiss from me.


PS How often do you guys change the carbon in your filters?
I'm not sure

We change the activated carbon once a term here.
Filter rinse once a week.
Filter change once every semester.
Partial water change once a week.
Test for pH, nitrites, nitrates, ammonia, dissolved oxygen once a week.
Complete tank empty and wash/scrub once a semester.

It sounds like you look after your tanks - someone has added something to the water for sure and that has killed most of your fish.

I have my suspicions about what happened...
Some of our staff are not very vigilant in watching students - if you all catch my drift!
One of these had a class in that room on Monday afternoon.
I think one of his students slipped into the Prep room and grabbed the 2M HCl that was in there for another teacher's prac...
My Prep rooms are vulnerable as the doors into the classrooms do not have locks - every now and then I will find a student wandering around in one of them!

The remaining fish are doing well this morning - their scales look a little battered, but they are swimming well - so maybe I removed them before too much damage done...

No locks on the doors??? Here we have locks on exactly everything and ALL doors have to be closed and locked at all times, even when you are in the room, according to my HT it is some kind of regulation, although I think she enjoys acting prison guard, hehehehe

CSIS Volume 2 Section 3.2 3.2 pg 15 (a) Preparation Rooms Paragraph 3 "Because the preparation room is often a storage area for chemicals, preparation room doors and or the perimeter doors should be locked when not in use, so that access through adjoining laboratories is not possible to unauthorized people."

HA! The designers of this school felt it was more important that emergency exits from the laboratories include access throught the preparation room that the door locks prevent me from direct access to labs not the other way around. Howzat!?!

Lou.

You must have had the same designers as here, Lou. We have a corridor that comes straight off the street entrance and the lock on my prep room door stops the door opening from the inside!
We have just bought some goldfish for testing (not sure how ethical that is - but it is the HT doing the testing- how do you argue?) and are going to give away those that survive!
Sue G

and are going to give away those that survive!

After some debriefing and appropriate counselling I hope.

Testing for what?

Hopefully you mean training them and seeing how much of a memory fish have - we've done that and it's great fun.

We also use our goldfish in our fish farm (comets usually) for introducing bacteria to our 5000 litre tanks a few weeks before releasing barramundi or silver perch fingerlings. After a few weeks holiday where they can stretch their fins they go back to their heated aquarium here in my prep room. They are a great indication of water quality and very hardy but we certainly have never set out to kill any! I haven't lost one in close to a year.

Please don't let them suffer, even putting marine life to sleep in a freezer is cruel. If your dissecting get mullet or Black fish and if your testing water quality use a data logger or 5 in 1 testing strips - not live fish. If your training them, get Oscars!

Mushroom.
Can you get some Stress Coat .. it may stop your remaining fish from progressively dying

A drop of clove oil to an aquarium will settle fish, it's what industry uses when transporting live fish the world over.

Thank you all for your input and sympathy.. I will follow your suggestions when I get the tank up and running again..
I asked the maintenace guy if he could make a huge metal cage with rings on the floor .. not to put the fish tank in, but to chain all the students up whenever they use that room!!!!!
He thought I was joking!