Lfs Cory'S Die In A Day Or Two

[Don Trinko]

I have had problems lately with cory's dieing in the 1st day or two. The tank I try to put them in has a ph of 7.3 and TDS of 750. It is a planted ( some criptocorns and water sptite. I very seldome fertalize) 20g with 3 sword tails, two rasbora and 5 serpae tetras. It gets regular water changes with 50% tap and 50% RO.
I thought I had found the problem when I discovered that the LFS water had a ph of 6.3 and a TDS of 900. This time I put the cory's in a plastic container floating in the tank with an air stone. I also added a little Amaquel+ in case of amonia etc. After 2 days of slowly adding tank water to get the ph similar to the tank ph I added the cory's. Yesteday they were fine, today one is dead and the other is inactive.
A little backgound on me; I am 67 years old and I have had tropicals since the 1950's I have 11 fresh water tanks and 2 salt water tanks. I have discus, Angels, bettas, etc and they are fine.
Any idea what is going wrong? Thanks; Don T.

 

[Curiosity101]

What does TDS stand for?

How long has the 20g been set up for? And is it just the 20g that is having the problem?

Why do you use half RO and half tap? Is your water particularly hard?

What are the tanks other stats? Including temperature.

Have you or do you medicate or dose the tank with anything on a regular basis?

What filtration do you have?

Have you had this problem with all corys, or just from a specific shop? And what species have you been trying?

Finally...the corys don't need more than a few hours aclimatisation for that difference. If you really wanted to go the whole hog I'd get a small bucket/container set up under the tank (5-6l) and then drip acclimatise them. This can be done with a piece of airline (as I'm sure you know from keeping marine fish). And just do it that way. Set it going, cover it up, check once an hour and possibly test the pH each hour.

 

[Don Trinko]

The 20g has been set up for several years. It has a power filter (100gph I think) and a sponge filter. The light are a total of 40 watts and are on abought 11 hours a day.
TDS is total disolved solids. It is not the same as hardness but similar. I mix ro with tap because it doesn't produce as many deposits on the hood and glass and I mix it for my discus anyway so it's easy to use the mix for all my tanks.
My DH is abought 12, KH abought 15, ammonia =0, Nitrites =0, and nitrates = 20. I do not use co2 but I do occasioaly add a plant supplement that is mostly iron.
I know that cory's don't need a 2 or 3 day acclimitization but... They keep dying so I had to try something. Thanks; Don T.

 

[WILDER]

How many corys were in the cotainer as I won't take long to pollute.

Always test bag water in ph and temp so you know how long to climatise the fish for.

Were the corys showing any of these symtoms.
Looking pale or darker in colour.
Being listless and lethagic.
Any red sores of streaking on the corys.
Leaning to oneside on the substrate.
Turning upside down.
Did the corys look bloated or thin.
What does it look like when the corys go to the toilet.
Any signs of laboured breathing, gasping, darting, erratic swimming, flicking and rubbing, or excess mucas.
Is there a greyish white film on the corys.
What do the corys barbels look like.

 

[Don Trinko]

The cory's were Albino but I had the same problem with 2 bronze cory's several weeks ago.
They showed no symptoms dead or alive. I had an air stone in the plastic container and their were 2 small cory's. During the daytime I was adding tank water abought every hour. I also removed water from the platic tank and added a few drops of Amaquil+ occasionaly. They looked fine when I released them to the main tank and were active.
There was no damage to the dead fish otherwise I would suspect one of the fish in the tank was killing them. Don T.

 

[Tolak]

If it's the same shop I would suspect ill fish, or exposure to some illness. Add the stress from moving & differing water, and you have fish dying.

Start with a separate tank, add about half a dose of acriflavin to the water. Pick up some metronidazole, sprinkle this on some frozen brine shrimp, feed this only once daily for a few days. Next water change, no more than a few days later treat with copper.

I follow this procedure with fish I get shipped in, stress from shipping & acclimation is to be expected. The meds in the water keep external problems at bay until the fish are strong enough to fight them off on their own. The metro does the same for internal protizoans & such.

While I don't advocate medicating well fish, it sounds to me like the fish you are getting in aren't exactly well.