Cories Dying after 24 hours?

Hello!

So I have had problems with Cories for about 3 years. I was told at the pet store that cories could be kept alone with my Betta (obs not true but I didn’t know anything about them at the time). When I discovered they couldn’t be kept alone, I got some more but they kept dying, I kept trying, then gave up and got a bigger tank. My Betta was aggressive to any cories other than the original so I gave up.
My original Cory has always been doing great, he’s very happy, used to chase my Betta, and is about 2.5 inches long (hes huge). My Betta died, so I decided to get him more cories to have a school and be happier (as he’s supposed to be). However, all my new cories died within 24 hours! And they all looked chewed up, fins missing — I’m wondering if maybe my older Cory is just not friendly anymore after living with my Betta and he’s hurting them?

Tank is 20g, ammonia 0, nitrite 0, nitrate 2.5ppm, p.H 7.4 (but stable there, just the natural pH of my tank). Sand, not gravel, use tap water with prime added. Heated to about 80.

I acclimated the cories first with floating the bag, then adding water until the pH was equal to the tank (about 2 hours).

Sorry for the long post!

Edit: Current Cory is doing perfectly fine! I don’t want him to be lonely

 

Well that's just crazy. As far as the tank parameters go thats what you want. And there are no other inhabitants other than the Cory? Also the new cories looked completely healthy when you purchased them? I'm leaning towards that's one mean Cory, but i'd like to see what others have to say.

 

They looked healthy, pet store gets new shipment on Tuesday and I got them Wednesday. There were some dead cories in the pet store tank but the ones I got looked fine. Nothing else in the tank now but the one Cory. And he doesn’t hide or act depressed, eats 4 sinking pellets a day, very big and healthy looking.

Thanks!

 

There's always the possibility you got sick cories that were about to die anyway or the shock killed them and your big Cory beat them up after they died. But it sounds like you did a good job acclimatizing them.

 

I personally would not buy fish from a tank with dead fish. It shows a lack of concern from the employees, and it is just not a good sign. Yes fish die in transit and in the store, but they should not be leaving dead fish in the tank to fowl the water that is generally already overstocked.

But I don't know if mishandling at the store is why your fish died, it is a concern. Have you noticed your original cory being aggressive? Sometimes with significant size differences, there could be accidental injuries.

How long were the cories in the bag? there has been a lot of talk that acclimating fish for long periods allows a huge amount of ammonia to build up in the bag. And it is supposedly worse if the bag was closed for a long time.

I am curious how you came up with the 2.5 nitrate reading. I have heard of 2.5 ammonia, but I never heard nitrate listed that way.

 

What kind of cory? 80 might be too hot for the general population. I would recommend setting up a quarantine tank before you try again to protect your current cory from any disease the new ones might be carrying in.

 

Could be a problem with water hardness or temp. Also what species of cory; most are pretty hearty. What size aquarium ?

 

So they are panda cories, I left them in the bag for about 30 minutes floating, then moved them to a bucket out of the bag and added cups of tank water incrementally, to avoid ammonia spikes. I was worried about the dead fish in the tank but these seemed ok.
I live in the southeast US, at the beach, so my heater isnt actually on it just stays 78-80 because of where I’m at.
As for the 2.5 nitrate, it’s somewhere between 0 and 5, so I’ve estimated in the middle (lower than 5, higher than zero). I worked with African cichlids in graduate school and since our nitrates were always low like this we would estimate in the middle.
20 gallon tank, haven’t checked hardness (water hardness isn’t supposed to be super high in the area).
I’ve thought about ordering the cories online so I know they’re healthy and dividing the tank so my bigger one doesn’t mess with them.
Thanks for all the replies!

 

I would try a different species of cory; panda has a few issues and prefer cooler waters; they do have one advantage of being a little smaller. I would try one of the aeneus cory (they come in various colours) or sterbai. Both species are fine at 80 but they are a bit larger than panda. The optimal number is 7-10 but a 20 high is pretty small so i'd go with 6 or so just do to limited space.

 

Will my other Cory get along with another species? I just hate for him to be lonely, but if he’s accidentally aggressive I don’t know how I would work it. If there is a way to bring temp down I would try it but I don’t know of one.
If he isn’t hiding or scared now does he need to have more with him?

 

he is a panda cory? I would add more of the same species from a different source. I have heard that different species will "hang out" together but never act quite the same as if it were their own species. I know my loaches prefer their own species the most. I had one yoyo loach that was the only one left after several years, and even though I had zebra loaches in the tank, he started pacing, "going around and around in one area of the tank for hours at a time. And Finally, I found more yoyo loaches for sale but they were less than half his size, it took a while before they were zooming around the tank together.
"If he isn’t hiding or scared now does he need to have more with him?"
That's a question you have to decide for yourself.

 

Will my other Cory get along with another species? I just hate for him to be lonely, but if he’s accidentally aggressive I don’t know how I would work it. If there is a way to bring temp down I would try it but I don’t know of one.
If he isn’t hiding or scared now does he need to have more with him?

Your other Cory won't be the issue.
To be honest and as mentioned by others simply don't buy fish from an LFS / a tank that contains dead fish (The LFS shouldn't even sell those fish to you).

There is not such a thing as : the others looked okay. It simply is a no go.
Even your.old one is at risk when you do.

Get the same.species.as the bigger one.

BTW : swimming / chasing the Betta wasn't a sign of hapiness but of loneliness. It probably tried to interact with the betta. A lone Cory isn't happy

 

I’ll try to order some online from a fish breeder since I don’t have a nice lfs nearby (just a petsmart and petco and the fish are always in pretty bad shape there).
Thanks everyone!

 

Set up a quarantine tank for when your new ones arrive.

Try not to buy fish that have only been in the store for a day. Give them a few days so the dead, weak and diseased can be culled.

 

I’ll try to order some online from a fish breeder since I don’t have a nice lfs nearby (just a petsmart and petco and the fish are always in pretty bad shape there).
Thanks everyone!

I'd check aquahuna first; for cory they are fine and they have cheaper shipping with more liberal doa policy than most online vendors.

 

I wouldn't buy from a company that ships live fish via USPS. Once they shipped my order to the west coast ( I live on the east coast) and held it for a few days before finally shipping to me. I also had plants show up week late once. By then, it was a box of mush. The same holds for non living items in general. USPS has become so unreliable in the last couple of years that I would not rely on them for anything that time sensitive. Especially not living things.

Overnight and 2 day shipments are just a suggestion on their part. When the package actually shows up is often different.

 

I wouldn't buy from a company that ships live fish via USPS. Once they shipped my order to the west coast ( I live on the east coast) and held it for a few days before finally shipping to me. I also had plants show up week late once. By then, it was a box of mush. The same holds for non living items in general. USPS has become so unreliable in the last couple of years that I would not rely on them for anything that time sensitive. Especially not living things.

Overnight and 2 day shipments are just a suggestion on their part. When the package actually shows up is often different.

I'm going to disagree for two reasons when it comes to aquahuna. First unlike most mail order their doa policy is a bit more liberal; 2nd i live in the southeast and they are in the northwest but their priority package have always gotten here in 2 days (I have about 5 orders with them over the past 3 years). I do have two caveat with them - (1) frequently their fishes are quite young (small); this can be both a plus and negative; and 2nd they will not sex cichlid and in general i've been unhappy with their cichlid so i only use them for shoaing/schooling fishes (rasboras, tetra, cory, ...).

 

I'm going to disagree for two reasons when it comes to aquahuna. First unlike most mail order their doa policy is a bit more liberal; 2nd i live in the southeast and they are in the northwest but their priority package have always gotten here in 2 days (I have about 5 orders with them over the past 3 years). I do have two caveat with them - (1) frequently their fishes are quite young (small); this can be both a plus and negative; and 2nd they will not sex cichlid and in general i've been unhappy with their cichlid so i only use them for shoaing/schooling fishes (rasboras, tetra, cory, ...).

Eh, the are not infallible just like all the others. I ordered panda cories from Aquahuna. They took 4 days to arrive (including one day where I got an email that it was out for delivery, but didn't actually arrive until the next day for some reason.) All 6 arrived DOA. They refunded without hesitation, but what a waste. First and last mail delivery for me... at least for a long while.

 

I'm confidant that their decision to ship via USPS is a business decision and not for the best interest of the fish. I read their DOA policy, I don't see what's liberal about it. They want you to take a photo of the dead fish on the day it arrives and contact them about it within 3 days. They do provide a refund instead of store credit.

Yes, the other carriers are not perfect, but I've never experienced issues with UPS or FEDEX. I do read news articles about some of the issues caused by USPS, like when they lost the delivery of live chickens being shipped to my state. Hundreds if not thousands of chicks simply lost. It doesn't give you much confidence.

Twice in the last year we paid bills via mail 2 weeks in advance, but had to pay late charges because the payments didn't arrive in time.

Maybe I'm just cursed and others don't have these issues, but it has surely soured me on the USPS.

This isn't about the local post office. The local postal employees here are awesome and they do a great job.

 

I'm confidant that their decision to ship via USPS is a business decision and not for the best interest of the fish. I read their DOA policy, I don't see what's liberal about it. They want you to take a photo of the dead fish on the day it arrives and contact them about it within 3 days. They do provide a refund instead of store credit.

Yes, the other carriers are not perfect, but I've never experienced issues with UPS or FEDEX. I do read news articles about some of the issues caused by USPS, like when they lost the delivery of live chickens being shipped to my state. Hundreds if not thousands of chicks simply lost. It doesn't give you much confidence.

Twice in the last year we paid bills via mail 2 weeks in advance, but had to pay late charges because the payments didn't arrive in time.

Maybe I'm just cursed and others don't have these issues, but it has surely soured me on the USPS.

This isn't about the local post office. The local postal employees here are awesome and they do a great job.

Of course it is a business decision; the question is do you want to spend $12 on shipping for $20 dollar worth of fishes or $40. If you have the extra money and are willing to pay $40 then of course buying from a place that ship overnight is fine. However if you don't have the extra money then aquahuna is a good alternative.

Having worked with several of these stores i found aquahuna pretty liberal on the doa policy - at the end of the day it is up to you. I'm just saying for my money i'm not going to spend $40 on shipping for $20 of fishes.

 

I agree. I don't order unless I can justify the shipping $$. Therefore my orders are usually larger than $20. I'm not willing to put my fish at risk with the USPS. Unlike me, you have not had issues with shipping via the post office, so I understand why your willing to do it. I used them for years until problems started arising. There's a reason many suppliers stopped using them.