Cory cat being attacked or is it sick?

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IzzyWheelie

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Oct 21, 2020
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Hello I have a Julii Cory Cat who last night I found with light grey looking spots and damage to the dorsal fin. I was wondering if anyone can tell me if you think one of my other fish (female tiger barb and a male Mickey Mouse platy) may be attacking her or could she be sick with something. I found her like this last night, she is still moving and acting normal but I just want to be sure. I took some pictures

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FreshyFresh

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Welcome. Tell us more about your setup. What size is the tank? Does it contain just the 3 fish you mention? Do you have a means to measure for ammonia, nitrite and nitrate in PPM?

I couple things come to mind, but may be completely unrelated... Corys do best in groups. The more the better. Problem is, I don't think your tank size will support that. They can spook and dart around when kept alone, which may have caused the damage you see. Another issue is the gravel you have. Corys in nature sift through soft sand. They'll live on gravel, but it's rough on them.
 

IzzyWheelie

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Oct 21, 2020
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Welcome. Tell us more about your setup. What size is the tank? Does it contain just the 3 fish you mention? Do you have a means to measure for ammonia, nitrite and nitrate in PPM?

I couple things come to mind, but may be completely unrelated... Corys do best in groups. The more the better. Problem is, I don't think your tank size will support that. They can spook and dart around when kept alone, which may have caused the damage you see. Another issue is the gravel you have. Corys in nature sift through soft sand. They'll live on gravel, but it's rough on them.
I have a 10 gallon tank with the 3 fish mentioned and a nerite snail. I have had the Cory cat for at least a year and never had any problems with her before. All levels are good and there has been no big changes. She was fine the night before so it either happened after I went to bed or during the next day then I found it last night. She does hide a lot and will dart around the tank occasionally. I have a feeling my tiger barb may be picking on her. The barb has a bit of an attitude and I have seen her chase the Cory around the tank a few times but she swims away as soon as I go near the tank like she knows she has been caught (haha). I have checked the barb and platy and they don’t have any signs of the same thing on them. So I think she is either getting bullied or catching herself on something
 

FreshyFresh

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Unfortunately I can't help with "all levels are good". I don't know what that means.

TBs can be jerks and again is another fish that should be kept in groups, the larger the better. This way they keep the pushing and shoving among themselves.

The fish you have aren't really suited for a 10gal tank.
 

IzzyWheelie

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Unfortunately I can't help with "all levels are good". I don't know what that means.

TBs can be jerks and again is another fish that should be kept in groups, the larger the better. This way they keep the pushing and shoving among themselves.

The fish you have aren't really suited for a 10gal tank.
I only recently found out that barbs do better in groups but I can’t really do a group of them with my set up. My local fish store told me those fish would be fine in a 10 gallon but didn’t tell me until recently about the barbs. I’ve had my tank for 3-4 years and never had this problem and have had a variety of fish. As for the levels I don’t know their exact numbers at the moment as I am not with my tank but they were all with in the normal ranges when I checked 3 days ago.
 

FreshyFresh

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Store employees generally give poor fishkeeping advice. I know there's knowledgeable ones out there, but it's rare.

For the meantime, I'd be sure to do a weekly 50% or more water change, feed lightly with quality ingredients list foods and monitor your cory.
 

IzzyWheelie

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I will definitely keep an eye on her and do water changes. Do you think it’s more she is sick or injured?
 

FreshyFresh

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Hard to say. From the pics the fish looks to have bright eyes and decent color.

Have to watch to see what's going on. If it's aggression, re-home the aggressor. If not, up your water changes and monitor.
 
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Just to add to the above. Injured/harassed fish are stressed. Stress is one of the major gateways for disease and parasites. This means your cory is more at risk. Further, fish which are normally out and about which suddenly go into hiding are usually doing so as a defensive measure. They hide from any harassment etc.

I cannot say that your cory has no disease issues for sure. I do know what has been said about tiger barbs is correct. They can be nasty little fish and the best way to blunt that aggression is to keep them in bigger numbers. There is one disease which can manifest in the way your fish looks. This is columnaris (Flavobacterium columnare). It is often called by several common names, cotton mouth, saddle back (because of the whitened area at the base of the dorsal).

This disease comes in a variety of strains. The most virulent kill so fast one rarely sees any symptoms. This is clearly not the case with your fish. Other strains are less virulent and can be treated. However, it is important one not medicate a fish unless one is reasonably certain of what it is they are treating. Please do not conclude you fish has columnaris at this stage. What I do suggest is water changes and closely monitoring the cory. If more white splotches appear, if you can spot what looks like fungus around the mouth of the fish, then you should conclude it is columnaris and it must be treated.

Treating columnaris is challenging because it usually needs antibiotics and this disease has developed resistance to the most commonly used- amoxicillin, doxycycline, benzylpenicillin and tetracycline. If you can determine this is the issue, I can point you towards a potential combo-treatment that has proved to be 70% effective, The problem is it will likely cost way more than you will want to pay. You would need a three drug combination and that can cost $50-$75 (maybe more). This will treat way more fish/water volume than you need to medicate, but one cannot buy meds in tiny amounts.

For sure, I would figure a way to get rid of the tiger barb- i.e return it to the store or give/sell it to another fish person since you cannot up the numbers significantly. Please do not kill it. Fish are not evil killers, some have just evolved to be more aggressive. One cannot change the inherent nature of a fish. You cannot teach a piranah to become a vegetarian.
 

fishorama

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I agree with both Freshy & TTA. For right now I would go with large water changes (50% or more) every day or at least every other day. Clean water can help with some problems...but that dorsal (top) fin spot seems deeper than just a surface injury unlike the other 1 near it.

I'm sorry we can't offer more help yet. You don't want to just dose random meds until you have a better idea of what's wrong & what to use.

I would give away the barb ASAP either to a shop or offer it on a neighborhood forum. We can talk about your small tank stocking problems when these issues are resolved. Good luck! We'll try to help more soon, don't be a stranger.
 
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