Cory fishes not eating, swimming near surface

[Ersy]

Hi, I am quite new to the hobby and slowly built the first tank over the last months and I am a bit concerned with my Julii corys.

Since 3/4f days 4 out of the 5 we have started behaving in a really strange way, spending all time either sleeping on the top of leaves (close to the surface) or swimming erratically near the surface (but it doesn't seem swim bladder to me). One, in particular, seems pretty bad and is just swimming near the filter output and keeping mostly vertically. I have been watching them and they don't seem to have been eating anything for 3/4 days now. They seem quite responsive though and two of them have come down to the bottom for a few hours, but still not eating.

Before this happened I had left a big tapper ware on the water obstructing 1/6 of the water surface for a few days (I used it as an emergency quarantine tank for 3 neon that had some cottonmouth and died with an overdose of Myxazin, stupid mistake).

could the simple change in the landscape have stressed the corys so much? After removing the tapper ware we did a big water change and added some PH Acid corrector (given to us by the LFS) and the fishes are generally a bit stressed afterwards (we did this only 3 times).

Water parameters are not great but still acceptable (I have Aquavital test so no testing for ammonia levels but I assume it's zero as nitrite has always been zero). Nitrate was slightly too high but it has been below 25 for the past day. Ph between 7/8, water is hard unfortunately, over 14 GH, so I used bottled water the last time and is a bit better now.

Tank is 60 lt, very well planted, we have about 12 neon, 8 rasboras, 4 danio erythromicron, 4 cleaners fishes (no idea whats their name sorry, but they are not corys!!), 5 corys and a lot of amano and cherry shrimps that have started reproducing like crazy since a few weeks

What shall I do with the Corys? just wait? change water? I read other posts reporting similar behaviour before them dying. Is there anything I could do to make sure they are fine or at least try?

Thanks!

 

[AdoraBelle Dearheart]

Do you have an airstone? Does the filter disturb the water surface enough to allow for good oxygen exchange?

I'm wondering if the tupperware covering the surface prevented a lot of the usual gas exchange, reducing the available oxygen in the water.

What temperature do you have the tank at?

For now, yes, keep doing daily water changes. Fresh clean water is the most important factor for fish health. Don't use the pH adjuster, pH 7-8 isn't what's causing the problem. Long term, the softer water fish will need softer water, but that's an issue of long term health/retaining too many minerals, not a short term issue, and adding chemicals like pH adjusters to tanks always makes me nervous. Cories are especially sensitive to meds and chemicals, and swings in pH are much worse than being kept in the "wrong" pH. Just use fresh water, declorinated, and temperature matched to the same as the tank temp before adding it to the aquarium.

 

[AdoraBelle Dearheart]

If you can post photos of the 'cleaner fish' that you don't know the species please! Someone will be able to ID them for you, and it's important, since some species sold as inoffensive, cleaner fish turn out to a larger, fairly aggressive species when they grow. So best to make sure of what they are sooner rather than later

 

[Ersy]

Do you have an airstone? Does the filter disturb the water surface enough to allow for good oxygen exchange?

I'm wondering if the tupperware covering the surface prevented a lot of the usual gas exchange, reducing the available oxygen in the water.

What temperature do you have the tank at?

For now, yes, keep doing daily water changes. Fresh clean water is the most important factor for fish health. Don't use the pH adjuster, pH 7-8 isn't what's causing the problem. Long term, the softer water fish will need softer water, but that's an issue of long term health/retaining too many minerals, not a short term issue, and adding chemicals like pH adjusters to tanks always makes me nervous. Cories are especially sensitive to meds and chemicals, and swings in pH are much worse than being kept in the "wrong" pH. Just use fresh water, declorinated, and temperature matched to the same as the tank temp before adding it to the aquarium.

Thank you so much. No I don't have an airstone but I read corys are fine without as they can 'gulp' for oxygen (and in fact they were doing that quite often before, now only 2 do that, the others are just lethargic, etc). the filter moves the surface quite a bit but perhaps not enough. Is there a way to measure oxygen levels and see if I need an air stone?

Temperature is currently set for 23 celsius

In the meantime, I'll do another water change, thanks a lot. Yeah, I am also a bit nervous about the PH conditioner, I won't use it again, thank you!

 

[Ersy]

If you can post photos of the 'cleaner fish' that you don't know the species please! Someone will be able to ID them for you, and it's important, since some species sold as inoffensive, cleaner fish turn out to a larger, fairly aggressive species when they grow. So best to make sure of what they are sooner rather than later

I found out who they are! 2 Bristlenose Plecostomus, 2 Octocinclus

 

[AdoraBelle Dearheart]

I found out who they are! 2 Bristlenose Plecostomus, 2 Octocinclus

Oh man. Oh man. Please, please don't take advice from whoever is advising you that these fish are fine for your tank!

Any chance of returning the bristlenose? They are a smaller pleco, but a 60L is really too cramped for one of them, let alone two. If they also turn out to be two males, they're gonna fight in such a small tank.

Plecos are also poop machines, you're going to be having problems with water quality with so many fish in such a relatively small tank, especially with two plecos in there!

Otocinclus are lovely little fish, great cleaners, but also are a soft water fish, and really need to be kept in groups of 5-6 or more.

 

[FishGuest5123]

My cories let me know if my nitrates are getting high by ducking air and staying at the top. I had one doing this the other fir most f day. Finally checked parameters and nitrate as over 40 which is unusual for that tank. I did a 70% water change and within a couple of hours, the Cory was back down with the others. Check your parameters with a liquid test kit and do large water change. How long has your tank been up and running?

 

[Ersy]

Thank you so much. Frustrating, as I repeatedly asked the lady in the fish shop whether it was fine to add the Plecos and the others (actually watching more pics I think they are the one in the pic below, so not Octocinclus)..eventually she just wanted to sell more. I can try and give them to a friend, and keep just one Pleco? she convinced me to get them to keep everything clean as I was having issues with other fishes getting sick... sad story

I had the tank since October, the corys for a couple of months, I added them with the other cleaners and they have been fine since a few days back...

I'll do a bigger water change tomorrow. I only managed to find a really crap test kit with strips so it's hard to tell whats happening there so I'll get one too.

Thanks so much! there is so much to learn!!!

 

[FishGuest5123]

Thank you so much. Frustrating, as I repeatedly asked the lady in the fish shop whether it was fine to add the Plecos and the others (actually watching more pics I think they are the one in the pic below, so not Octocinclus)..eventually she just wanted to sell more. I can try and give them to a friend, and keep just one Pleco? she convinced me to get them to keep everything clean as I was having issues with other fishes getting sick... sad story
View attachment 132555

I had the tank since October, the corys for a couple of months, I added them with the other cleaners and they have been fine since a few days back...

I'll do a bigger water change tomorrow. I only managed to find a really crap test kit with strips so it's hard to tell whats happening there so I'll get one too.

Thanks so much! there is so much to learn!!!

We all began just like you are. In a year you’ll be spitting out advice on everything.

 

[Ersy]

thank you

 

[AdoraBelle Dearheart]

Thank you so much. Frustrating, as I repeatedly asked the lady in the fish shop whether it was fine to add the Plecos and the others (actually watching more pics I think they are the one in the pic below, so not Octocinclus)..eventually she just wanted to sell more. I can try and give them to a friend, and keep just one Pleco? she convinced me to get them to keep everything clean as I was having issues with other fishes getting sick... sad story
View attachment 132555

I had the tank since October, the corys for a couple of months, I added them with the other cleaners and they have been fine since a few days back...

I'll do a bigger water change tomorrow. I only managed to find a really crap test kit with strips so it's hard to tell whats happening there so I'll get one too.

Thanks so much! there is so much to learn!!!

Yeah.... I think she's just trying to sell you more fish I'm afraid..

Young bristlenose are good at cleaning algae. But algae is harmless. The amount of ammonia that a pleco produces - let alone two of them in only 60 L of water - is not harmless at all. And as I said before, plecos are territorial, and won't be happy to share such a small territory, especially if they both turn out to be males.

Even if you only keep one pleco, I'd upgrade the tank size to at least a US 20 gallon/75 L tank, ideally larger, since you have a good number of other fish too. If you want to keep both plecos, at least a 40 Gallon/150 L aquarium. Footprint of the tank is also important for plecos and cories, so a tank that's longer rather than tall, since the tall space is wasted on most fish, especially bottom feeders.

The fish in the pic is a hillstream loach, also called a borneo sucker. Not a problem, and good algae eaters.

Don't worry too much about algae though. Algae doesn't harm fish at all, clean fresh water with zero ammonia or nitrites, and low nitrates, is the most important thing for fish health. So especially while you have so many fish with high bioloads, and while you're not able to test the water yet, large daily water changes will give your fish the best chance to ride this out.

But yes, please don't listen to that woman! She's mis-sold you some fish, and sold you products that might well cause more problems than fix them. I'm sorry that was your intro into the hobby! It happens to a lot of people I'm afraid, so you're not alone. Research the fish you currently have, especially tank sizes, compatiability, adult size, preferred water parameters etc. I wouldn't add any more fish anyway, you're well stocked right now, and removing at least one pleco will help. But focusing on doing your own research rather than relying on the fish store, for sure! Seriously Fish is a fantastic, accurate resource, because there's also a lot of mis-information online too, so I know that can be really confusing. Wet Web Media is also a great resource, written by people who have decades of experience in the hobby. Plus this forum of course

 

[azvictoria]

I had a pleco once that started eating slime off my fish - it was quickly evicted and the last one I ever owned. Corys are likely too quick at first, but it may not take much once they're slowed by assault or other reasons. I'd rehome the plecos...not just for the chance yours are doing the same, but for all the other reasons people have mentioned. The otos are terrific and serious cleaning machines without the trouble of becoming parasites - at least not that I'm aware of. Corys definitely like the bubbles of an airstone.

 

[Gypsum]

Sorry you've had such a rough entry into the hobby.

The hillstream loach isn't fine, because they are from cool, fast-flowing streams, so they require fast-flowing and very clean water. Some of the other fish, like the neons and the rasboras and your danios, are from slower moving water so would not appreciate the amount of flow the loach needs. The loaches should have at least 20g and won't tolerate an overstocked tank for long.

You should get yourself a 30-ish gallon tank, add a powerhead, and move the corys and the hillstream loaches to that one.

 

[AdoraBelle Dearheart]

Sorry you've had such a rough entry into the hobby.

The hillstream loach isn't fine, because they are from cool, fast-flowing streams, so they require fast-flowing and very clean water. Some of the other fish, like the neons and the rasboras and your danios, are from slower moving water so would not appreciate the amount of flow the loach needs. The loaches should have at least 20g and won't tolerate an overstocked tank for long.

You should get yourself a 30-ish gallon tank, add a powerhead, and move the corys and the hillstream loaches to that one.

True, I shouldn't have said it was fine, it's not ideal for the loach, I meant fine as in, not going to cause water quality or aggression problems. But the soft water fish and types of flow etc aren't fine, you're right.

 

[Gypsum]

True, I shouldn't have said it was fine, it's not ideal for the loach, I meant fine as in, not going to cause water quality or aggression problems. But the soft water fish and types of flow etc aren't fine, you're right.

No, it won't cause that. But it's super sensitive to water quality. They also like to live in groups. I would love a small shoal of them, but I don't have any tank with room and the right set-up these days.