One of my tetras is very thin - worried it might be a parasite?

[PigOnRollerskates]

I have 5 neon tetras, as well as 5 platys and a plec in a 70l tank. I've had the tank since the spring, and the 5 tetras were the first fish I bought after cycling, and have all done very well so far.

When I got them they were all the same size and seemed very happy. For the last couple of weeks I've thought one of them looked skinnier than the others, and looking properly tonight one of them looks like it's wasting away to nothing.

I've googled and found links to parasites but it seems strange that just one would have such a drastic reaction? Surely if one had parasites they all would by now?

Is there any other explanation for one fish from a group suddenly looking so thin?

If it's relevant I did also have 2 guppies that both died within a few weeks of arrival. One on the first day so I put that down to stress of the move, and one within about 2 weeks, with no explanation.

[EauRouge]

There's always one fish that gets it first. Is he eating and pooping OK? It could be a parasite, a bacterial infection or neon tetra disease- getting skinny is a symptom of a few different things. Have you got water readings? Any other symptoms- what does his poo look like? Is he swimming OK? Are the other fish beating him up?

[PigOnRollerskates]

Hi Eau

Thanks for that.

I don't think he's eating. I just fed them and he swam around near the others but didn't eat anything. I haven't seen him pooing at all but then I haven't seen the others pooing either.

Water readings:

pH 7.4
Ammonia 0.25
Nitrite 0
Nitrate 0

The ammonia is a bit weird as it's always tested at 0 since I've had fish in. I wonder if it's high because I got 4 new platys about 10 days ago? Can't think why else it would be.

The pH seems high too. I did a 20% water change last Saturday which was more than normal because I moved the tank and emptied most of the water into plastic boxes then refilled with the same water. I ran out of boxes so I had to put 2 full buckets in on Saturday. I would normally do a 10% change each Saturday.

I don't think he's getting beaten up. I haven't witnessed anything and I've been watching quite a lot. He seems to be swimming fine.

I've now noticed that one of my platys (a baby who seemed to have made it through) is nowhere to be seen. I'll be gutted if he's died. He was my only ever successful live birth. He was getting quite big and almost as big as a tetra. I haven't seen him today or yesterday and he's normally the first to the food (typical teenager).

[EauRouge]

Is the pH higher than normal? What's your tap water pH like? Is the tank very heavily planted or is your tap water nitrAte low? It's unusual to have a nitrAte reading of zero.

[PigOnRollerskates]

The pH is often a little high, but usually a tiny bit lower than that. I have the API Freshwater Master Test Kit, and I usually use the normal pH tester, and it reads at about 7.0 or 7.2 depending on when I last did a water change. Today when I did it I thought it was reading more like 7.6 so I did it again with the High Range bottle and it came out as 7.4.

My tap water is neutral I think, but I've only tested it once. I'll do it again later when I've got a chance. I live in the high peak and so I always assumed my water was quite acidic but it doesn't test that way.

The tank has 3 plants in it, and I only bought them 10 days ago, before that there were none in it because they'd all been eaten! It had been a few weeks since I removed the remnants of the old ones because they were floating about.

[PigOnRollerskates]

I did a tapwater test tonight and it's 7.0. The skinny tetra still hasn't eaten anything. Should i try some medicine?

[neontetra]

Just from personal experience (I know very little) I'd be wary of adding medicine to a tank where most fish are healthy, as you can just start to create a sort of chemical soup for them to swim in, and maybe your one poorly fish is just elderly, or may have a genetic disorder. Just personal experience though, I basically know nothing. Good luck!

[MurderOfHusbands]

Is the neon tetra still alive today? Any others looking ill?

First observation is your tank isn't actually cycled properly. You are saying it is, but the proof is in the pudding. You should read some NitrAte.

Forget pH for now - a swing between 7 and 7.4 isn't unusual, as pH shifts a lot for all sorts of reasons and mostly fish aren't phased by this. I'm more concerned about how little water you are changing weekly. 20% is what is normally touted as minimum weekly change, and I personally advocate nothing short of 30% UNLESS you have extremely high plant mass in the tank, which would be eating up all the nitrates, excess ammonia, etc.

From here, you have a few priorities - regular, every day/every other day water changes until the tank is cycled again. 20% minimum a day. Also, buy some Seachem Prime - its dechlorinator, but its extremely concentrated so it'll last you ages (one bottle lasts me a year or more sometimes, when i had smaller tanks) and it also detoxifies ammonia and nitrites if you double the dose. If you get a really major spike of ammonia or nitrite, put a double dose in the tank and do a water change.

[PigOnRollerskates]

Hi Murder

Yes Twiggy is still with us, and the others seem fine, but I lost a platy on Friday, and yes I agree that the tank wasn't cycled properly. It had been reading fine but I think adding 4 platys and the plants all in one go meant it didn't cope. I have bought some Stress Zyme to add extra bacteria, and I did a 20% (maybe a bit more than that) water change yesterday and the day before.

Fish shop staff advice was to now do 20% every other day and test daily until the ammonia is back at 0. Also to be very careful about overfeeding, which I think I was doing.

I didn't realise that about water changes. I thought it was 10% weekly or 20% fortnightly. Not sure where I got that info from. i will now do 20% weekly from now on.

I've just ordered some Seachem prime online, as I won't be able to get to the fish shop now until next Saturday.

I've been googling about my skinny tetra, and I'm pretty sure whatever it is will have been caused by poor water quality, but it still might be a parasite or other disease. I read on one website about adding crushed garlic. Has anyone heard of this? Is it worth a try?

[MurderOfHusbands]

I've heard of using garlic but not tried it myself. For now I'd say get on top of the cycling issue and wait and see. Do you feed any live or formerly live food, such as blood worm or daphnia? That may help - half a frozen cube of daphnia or blood worm once a week is always good. I wouldn't start treating for parasites until sure - medications are a pain, and treating when unnnessicary could be detrimental to the whole tank's health. Good luck with it! Sure it'll be fine. IMO, if it was something too bad you'd see a whole lot more dead by now.

[PigOnRollerskates]

Update: twiggy has disappeared without trace. The remaining 4 neon are looking fine though. I have been doing water changes every other day and I've just tested again.

Nitrate and nitrite are both still testing at 0.

Ammonia is back to 0.

Ph has gone really high. Off the chart so I'm not sure exactly.

I have been adding the prime and some stress zyme.

I don't know what else to do. Do i just carry on? All remaining fish seem healthy but high Ph is worrying. Plus I'm scared to introduce any more fish in case it all crashes again.

What nitrite / nitrate readings do i want?

[MacaYoniandCheese]

We lost our whole tank to a parasite a few months ago. We first noticed that one was affected and then they all dropped off in a matter of days .

[EauRougemasTree]

The pH has gone high? How high does your test go? Neons aren't massively picky but sudden changes in pH can cause problems for any fish.

[MrsBobHale]

Well I just tested pH again and it's back to normal range now. It's in the pale green zone where I can't tell the difference between 6.8 and 7.2.

I also did the High Range test and it was paler than any of it.

Yesterday I tested just before doing a 25% (possibly more) change.

It was definitely off the normal chart, and even on the high range it was a deep purple, possibly 8.8 but hard to tell.

I have put some rocks in there fairly recently but they all passed the vinegar test. I will monitor it daily this week and if it goes up I'll get the rocks out.

It's odd though because it's now nearly 24 hrs since i did the water change, and yesterday it had only been 3 days since I'd done a similar water change.

Could the fact that the tank wasn't cycled cause the pH to go up?

[MrsBobHale]

Oops sorry - just realised I've namechanged. It's Pig btw!

[EauRougemasTree]

The pH can fluctuate a bit during the cycle but I'd suspect the rocks to be the cause of it. Do you know what sort they are?

[MrsBobHale]

It's gritstone as far as I know. There is also one bit of flint.

I also had a lovely fossil that I found in Dorset, but parts of that fizzed when I put vinegar on it so that didn't go in.

[MurderOfHusbands]

7.2 isn't high, really. All local tap water where I am is at least 7.4, and all my fish are in that, as are most every other fish keeper round these parts. You can also have soft water thats a high PH and so on.

Don't get hung up on ph.

With nitrate, you want to be seeing some of it. Once you see NitrAte, and zero ammonia and zero nitrite you are cycled. I have to admit wondering if your test kits are duff if you're not seeing anything - ammonia, nitrite or nitrate.

With your nitrate test, the test kit with the solution in, before testing, bang it very bloody hard against a table/your leg/what-ever. I know that the mixture can separate in the bottle and become a bit viscous.

Sounds like you're not having much luck right now, but stick with it.