My Fish Died

[MinnowMiss]

I have a 25l fluval chi which I cycled using household ammonia as per the a fishless cycling article from another forum. The nitrites and ammonia were zero so I did a 75% water change and tested again (no nitrates, ammonia or nitrites). I added some soaked bogwood and 2 new plants then a few hours later got 6 White Cloud Mountain Minnow, except there were 7 in the bag when I got home. I floated them for 20 min, then added my tank water and left for another 20min with lights off then netted them and put them in my tank.

They were in the pet shop tank next to some poorly looking goldfish under treatment (not sure what for), but they lady showed me the separate filter and water feed that they have, and all the minnow looked healthy. I fed them once last night (on aquarian goldfish flake crumbled fine) and once this morning because I was so excited to finally have fish. I know this is overfeeding and was planning on next feeding them tomorrow. I have also put in the recommended dose of melafix given the other fish in the shop were poorly. They were fine and swimming around this morning but all were very dead when I got home from work 12 hours later. I tested the chemistry and the ammonia and nitrite were 0, and the nitrate 5.

My questions:
- did my overfeeding cause this? If not, any ideas?
- just in case it's contagious how can I disinfect my tank without ruining the filter medium (or do I have to just start over again)?

 

[Lolly123]

Im no expert on fish medication or disease, but putting in medication for fish that were showing no signs of disease at all, i'm not sure if thats a good thing or not...? I know you said that the other fish in the tank next door were ill, but if yours were fine and had no signs of ill health then im not sure if this could have affected them, as well as going through the stress of being brought home and put in a new aquarium. Maybe i'm wrong on that, im sure somebody with a good background in fish disease and meds can advise further or more accurately.

Good job on the fishless cycling though, how long did it take, did you allow for the week of having consecutive 0 readings for ammonia and nitrite?

Also what test kit do you use, is it a decent liquid test kit or the strips?

I understand that fishless cycling is the best way to start and that you can normally stock quite well off the back of that, but maybe 7 new fish was pushing the boundary a little.

Im sure someone else will come along and give you more info, or rip my post to shreds

 

[MinnowMiss]

Thanks for your reply.

I use the nutrafin liquid test kit and have a little book with all my readings over the past five weeks. I wasn't aware I needed to leave a week of negative readings - I had just 2 days. The melafix bottle had a dose for adding new fish, and I remember adding various treatments as a preventative when I was a child with a tropical tank.

This has kind of shaken my confidence in the fishless cycle. I guess I need to throw out my new plants, the gravel and filter media and start again, in case it's an infection. I've tried rinsing everything (except the filter media, just in case it can be saved as I don't want to waste 5 weeks' work) in boiling water and putting it back in. I do have the offer of some mature filter media I can collect from a show in a couple of weeks, so I could just start over.

Thanks again. Fish are much more complicated than I remember.

 

[karin]

Don't throw anything out. That would be a panic response.

With little fish, sometimes there are just bad batches. And with a new tank, there are bound to be some fish death. So....

Try a week of dosing with ammonia and see what your biological filter is up to. If it is still producing double zeros then in a week do a huge water change and try fish again. Go to a better shop if you can.

I also would not medicate unless you started seeing problems. It could be that the new tank and the medication were quite a shock to the minnows and caused death. What was the temperature of the tank? I'm not a minnow expert but make sure you have the right temp for them. Oh and what is your Ph?

Again, chalk this up to learning.

 

[Lolly123]

I would agree with karins post, keep dosing for a week until you get zeros, and then try again. As said, the minnows require quite a low temp if I remember correctly. Your PH would be good also, I believe that ammonia can be more toxic the higher the PH value.

Don't be disheartened, you'll get there, maybe try a different shop and if you buy fish when your tank is ready again, maybe try 1 or 2 less than you originally bought to be on the side of caution. Whenever I buy fish, I always spend about 5 mins looking at the particular tank I want to buy from, colouration, body shape, gills, eyes, behaviour etc those things are all on my list to look for and if I suspect the tank is not quite up to standard, I just don't buy. I like to study the majority of the tanks in the store and if there seems to be pattern of good healthy fish I feel quite secure in buying, if its the other end of the scale and im seeing the opposite then I'll leave without a purchase. This works for me because i've got a good selection of fish stores around me.

Anyway, keep us updated, will be interested to see how you get on.

Good luck