Fish Deaths

[Stevo87]

Hi

I have a 180 litre tank that's has been up and running for 3 months (upgrad from a smaller tank). I had 5 neon tetras, 3 platys, 5 otos, 3 small silver sharks, 6 guppys, 3 mollys, 4 danios and 2 amano shrimp. I added 4 cardinal tetras and 3 cherry shrimp on Saturday and since then 3 cardinal tetras, 1 danio, 4 guppys and 1 neon tetra have all died!

My readings as of this morning are

Nitrate 10
Nitrite 0
Ph 6.8
Ammonia 0 - 0.25 ( I find it really difficult to distinguish between the two colours on the test kit)
Kh 6
Gh 4
Temp 24

I had been doing weekly 25% water changes but since the deaths I've done 25% on Monday and 50% yesterday. This hasn't stopped the deaths as another guppy died this morning and another one looks on its way out just now. It has holes in its back fin which where in perfect condition yesterday and isn't moving very much.

All the fish seem healthy and active up until a few hours before they die. They are all peaceful fish and haven't noticed and bullying or fighting.

Yesterday I added aquarium salt and started treating with melafix.

I honestly have no idea what could be causing this, if anyone has any ideas it would be much appreciated.

Thanks

 

[attibones]

First of all, you are quite overstocked. The silver sharks definitely need a larger tank. Excluding the sharks, and before the deaths, you had about 56 inches of fish for a tank at almost 48 gallons.

Sounds like one of the new fish brought something in, like fin rot. However, fin rot can sometimes be the last thing we see. What does the fish poo look like?

Also, what filtration are you running? You said this tank has been running for three months. How did you cycle it?

Bump up the temp a few degrees. Danios prefer colder water, so you don't want to raise it up too high, but warmer water helps with healing.

 

[mark4785]

If your fish have fin rot you need to correct this by doing a 100% water change to remove any ammonia in the aquarium. Raising the temperature with a total ammonia value of 0.25 ppm is something you should never do because total ammonia comprises two components, one of which is the deadly free ammonia ion and the other being ammonium which is relatively harmless; the deadly free ammonia ion becomes more dominant when you HIGHER the water temperature and the pH level. While I can respect Attibones attempt to help the OP, I cannot understand or support his/her advice to higher the temperature of the water.
 
What you need to do is remove all of the water from the aquarium and replace it with fully dechlorinated tap water of the same temperature and which has similar KH, PH  and GH values. I would recommend using a dechlorinator which protects the slime coat so as to prevent any fluctuations in ammonia from so easily burning the fishes skin and gills etc. Aloe vera is the protective skin additive to look for ideally.
 
Once you have a total ammonia level of 0 ppm, which will appear a distinct yellow in an API ammonia test vial, you then need to treat the aquarium for fin rot, ideally with a veterinary grade antibiotic. Do not bother using the Interpret anti-bacterial range as from experience they just don't work.

 

[attibones]

I didn't know that bit about the ammonia ion. That's good information. However, if there is some sort of bacteria present, a higher temperature can help prevent spreading of the bacteria.

OP, I believe you should just ignore my earlier post. Mark4785's suggestion is much more sound than my own.

 

[the_lock_man]

Once you have a total ammonia level of 0 ppm, which will appear a distinct yellow in an API ammonia test vial,.

 
I have to disagree with this part. It is exceptionally difficult to distinguish between 0ppm and 0.25ppm under certain lighting, particularly artificial. I wholeheartedly agree with the rest of the post though.
 
Mark, where would you suggest we obtain veterinary grade aquatic antibiotics without visiting (and therefore paying the fees of) a vet?

 

[mark4785]

I have to disagree with this part. It is exceptionally difficult to distinguish between 0ppm and 0.25ppm under certain lighting, particularly artificial. I wholeheartedly agree with the rest of the post though.
 
Mark, where would you suggest we obtain veterinary grade aquatic antibiotics without visiting (and therefore paying the fees of) a vet?

 
 
 
A total ammonia concentration of 0 ppm will appear a distinct yellow with an API ammonia test kit. If it doesn't appear yellow some argue that the chemical reagents are interacting with what you are putting into the water (possibly nitrate or phosphate fertiliser) or the ammonia level is above 0 ppm.
 
You would have to take the ill fish in a plastic container with a portable heater to a Veterinary surgery or pay them for a home-visit. Alternatively, obtaining veterinary antibiotics like metronidazole can be obtained from discountedpetproducts.net .
 
In my view money should never get in the way of treating a living thing whether that be a fish or a dog. If money was an issue I wouldn't buy the said pet(s).