I’m really hoping someone can help me... essentially my whole tank died overnight and I’m baffled as to why?! I fed everyone as usual on Tuesday night and all inhabitants were great (I actually thought to myself how healthy and happy everyone looked!) then when I checked everyone on Wednesday morning the whole tank apart from 3 Red Tail Black Sharks (that were cowering at the bottom/back of tank) were dead!! After I had netted all of the deceased out - I checked the water with a quick dip test and all came back OK (I’ve got a master test kit on order but I used up my last drops last weekend hence the back up 5in1 test strips). Water temp had gone slightly high to 29degrees – usually 25/26degrees but other than that and a slight cloudiness everything seemed perfect.
Please can someone help me figure out what happened? I’m devastated and so frustrated that I don’t know the answer! I do water changes religiously and am always careful not to overfeed. I slightly altered the aquascape with rock around 4 weeks ago but haven’t had even a hint of any illness or stress related behaviour etc.
Tank and fish list as follows: Juwel Rio 350 LED (3.5 years old) Manufacturers heater and internal filter. AquaSKY lights x2 (1 year old) Plants all from LFS and range between 3 years and 4 weeks old.
10 x Bentosi Tetra – Approx 1 year old (Dead) 3 x Denison/Torpedo Barbs – Approx. 2 years old (Dead) 4 x Synodontis Petricola – Approx 2 years old (Dead) 5 x Glass Catfish – Approx 1 year old (Dead) 5 x Red Tail Black Sharks – Approx 1.5 years old (3 Remaining) 3 x Otocinclus - Approx. 2.5 years old (Dead) 1 x Cherry Barb – Approx 2.5 years old (Dead) 2 x Cardinal Tetra – Approx 2.5 years old (Dead) (Both the Cardinals and Cherry Barb were part of larger shoals in another tank that consequently got shut down and were transferred approx. 1 year ago.) 5 x Amano Shrimp (Dead) 1 x Bamboo Shrimp (Dead)
Please help – upset doesn’t ever cover it. Presumably this would apply for most of you but this tank really is my pride and joy and to have this happen is heart-breaking!
I also attach a picture of my tank from a couple of days prior to this (please excuse the glare in the photo the water was crystal clear).
It sounds like something sudden and catastrophic happened.
Unfortunately the 5-in-1 test strips don't cover ammonia to find out if it might have been a sudden ammonia spike (although the reason isn't clear) - if you still have the water, a LFS might be able to test it in the interim to see whether there's a high presence of ammonia (even if this may have dropped since). The other possibility is that the heater malfunctioned and the tank had got higher in temperature but had dropped to 29'C by the time you realised the problem - you could test its function out.
Ps. For the sake of the 3 remaining sharks, definitely ensure that you do a ~50% water change, just to reduce the tank of any ammonia or toxins that might be in it. (Beforehand, you can set aside some of the original water for ultimate testing for ammonia and with the new test kit.)