Corydora Sterbai under attack

**KaedeGwen** · 20th Dec 2012, 16:33

Hi, all, need some advice for my cories.

This 2ft planted tank has been up for 6 months and no live stock has been added to this tank recently. However, I just changed the filter and both of the filter I am using is a hangon filter, but the ceramic ring was from the old filter, so it's not exactly zero bacteria.

I did a 30% waterchange (every weekends) too as this tank is quite heavily stocked. Did a heavy pruning 2 weeks ago. Also, I dose bacteria back when I do waterchange. No Ph swing too after the waterchange.

Yesterday when I was feeding, I notice my 3 only sterbai have this white patches on their backs and to my horror, one of the cherry shrimp actually cling on the sterbai and seems to eating it, the poor sterbai had to make a few dash to shake it off. After that, I saw one of my female guppies attacking the same white patch too. I feed my fishes every 2 days so I doubt they are starving.

I then quickly seperate them individually into breeding box and let them continue stay in the same tank. But of the of the largest sterbai was too big and refuse to stay still in the breeder box so I have it place in my quarantine tank.

They were perfectly healthy last week and I have other types of cories in the same tank but nothing have happened to those, they are 2 Cory leopard, 3 Cory habrosus, 2 cory pygmy and 9 otos. All these scaless fish is not under any attacks at all.

My question is:
1. Why only the Sterbai are under attacks of guppy and shrimps?
2. Why is most likely to cause the attacks?
3. How can I treat the white patches? (They are not fuzzy as of yesterday but 1 of the cories (The one in quarantine tank) patch turned a little fuzzy today)
4. Will there be a risk to release them back to the community when they are healed?

I am pretty upset over this as the largest sterbai is my very first fish that I have been keeping for a year and watching my passion in this hobby grows..

Thanks in advance.. >_<

**tetrakid** · 20th Dec 2012, 19:08

Healing any fish after desease is noticed is easier said than done. One can spend loads of money buying one chemical remedy after another, but usually using chemicals only cause the fish to become worse or develope other complications besides the original problem.

Since fish diseases usually develop disease in a period of time and not spontaneously, it is usually too late to restore the fish to a normal healthy condition when signs of disease becomes noticed by the hobbyist.

One should at least be mentally prepared to lose the sick fish.

**KaedeGwen** · 20th Dec 2012, 23:57

Actually, I am not very keen on using medication too, and this sterbai is quite strong as it suffered quite a few mouth rot since I begin this hobby due to my lack of knowledge.
They are still healthy at the moment just the white patch is still there, and I still couldn't understand why suddenly all the sterbai got attacked.. *puzzled*

Thanks for the advice, nonetheless, I try to prepare myself to lose sick fishes since small fishes don't really have a high chance of recovery as compared to bigger fishes or other types of pets..

Currently I am just trying to keep the water as clean as possible so that they will not be further infected by dirty water quality..

**Shi Xuan** · 21st Dec 2012, 00:50

Hi,

I can't exactly give you any good advice but I can try to narrate how it goes for my 2 ft tank, which is quite heavily stocked with invertebrates and fishes as well. I've never used any bacteria starter when I set up a new tank. Most of the time, I try to keep things simple, so all my tanks look really primitive. I use an air driven filter, which in my case, corner/box filter stuffed with filter floss. If it happens that I already have a matured tank, I simply remove a portion of the floss from the filter in that tank and add it to the filter I'm going to set in the new one. Then, gravel, some rocks, wood and plants.

Initially, I keep the bioload low because any sudden increment in stock level could cause a bacteria bloom and possibly affect the live stocks. The tank should be alright to stock more when I could observe some microscopic organisms in the water, algae growth or diatom on the tank surface and anywhere else. I do weekly water changes but not too much at the start, probably around 20%. The only time I do 40% or more water changes, is when the algae goes into full bloom. This should take some time between 1 - 2 months and afterwards, the biological filtration in the tank should be stable, more or less.

Biological filtration is the vital factor here. The filter floss consists only of a small proportion of bacteria colony. Most of them could be found elsewhere in the tank, on plants, rocks and other ornaments. Its also crucial to understand that whenever you feed the fishes, you are indirectly feeding the bacteria living in your tank.

Losing some fishes in the course of fishkeeping is inevitable, so don't take it to heart if you've tried your best to keep them well.

**KaedeGwen** · 24th Jan 2013, 06:06

Hi, thanks Shi Xuan, thanks for the advice.

Just some updates on my sterbai.

I kept them in a quarantine since then until yesterday for 1 whole month and the injuries definately improved. No more white patches. Thinking they already recovered, I released them back into the tank.
Just after 24hours when I check them again, the white patch came back and this time, 1 of my sterbai white patches are near red/bleeding. I quickly net them out again and place them in my dwarf cories tank since they keep getting attacks by other fishes and shrimps.

Will observe how they fare in this dwarf cory tank, perhaps will let them stay there for good if they get better in there.

But my dwarf cory tank is super small, poor sterbai gona squeeze a little with the small little fellows..

Until now, I still can't find the cause of this attack and attack until they have white patches.. X___X

**AQMS** · 24th Jan 2013, 15:52

did you clean the filter and replace the filter wool?

**KaedeGwen** · 24th Jan 2013, 21:03

Originally Posted by zerofighterx101

did you clean the filter and replace the filter wool?

Hi Zerofighterx, yes, I cleaned it regularly, nothing has been changed in my routine and the attack just happened randomly. But it's a little old so I changed some of the wool after yesterday as I saw one of my guppies getting some white spot frequently. It only occurs to that particular fish when the tank is dirty.. but it heals after a waterchange usually.

The sterbai are healthy and eating well though.. They are stirring up my sand scape for my dwarf cories pretty much by chasing eachother around for fun... like a big tank destroying the scape.. hahaha.. Well, to save the scape or save the fish, I rather sacrifice my scape and let them live in peace..

Hope they recover from the injuried white patch soon..

**AQMS** · 25th Jan 2013, 12:08

what do mean some of the wool?

**KaedeGwen** · 25th Jan 2013, 12:10

I didn't change all at once.. I have 4 pieces of wool in my filter so I replaced 2 and the old ones I just rinsed in tank water so that the bacteria won't be totally gone to keep the tank stable.

**AQMS** · 25th Jan 2013, 12:25

i suggest you should try to change it all even the 2 new pieces that you have put in.
There is probably parasite in the wool,that why the disease keep coming back.
That is just my opinion.
Try change all the wool rinse the the ceramic. Give it a fresh start.

**KaedeGwen** · 25th Jan 2013, 12:31

Oh.. I just recalled, not sure has it got to do with I changed a new filter..
Before that it was all ok.. The filter was consider pretty new like a month plus..
Will do some more clean up.. Slowly spread the cleaning over a small period instead of a major one in a day.. My tank quite heavily stocked so I am really afraid that I will kill all the bacterials at once..

If not will probably add another filter.. I am using hang on filter for now as I am going to redo my whole setup soon so not investing on canister yet..

**stormhawk** · 26th Jan 2013, 18:08

The white spot parasite is present everywhere, not just in the filter, so changing the wool is useless unless you deal with the parasite itself as a whole. Curing ich is fairly simple for most part. The use of ich medications like Sera Costapur, is good for combating this parasite. You can use salt in combination with heat around 32 deg C, however Corydoras react badly to salt in their water. Understanding the life cycle of the parasite will help you in your fight against it.

Doing some maintenance of the substrate will be good as well, as the cysts will settle in and among the gaps in the substrate before maturing and releasing the free-swimming larvae, which then infest the fish in the tank.