Silver Dollar Swelling

[Elisar]

Hey guys, tonight I was just looking at my tank and I noticed that one of my silver dollars had a ball shaped lump on the side of its body, Does anybody know what this is?
I'm 95% sure it isn't caused by the water or another fish as all my other fish are perfectly fine and when I searched the internet other people's silver dollars have to lump in the exact same spot but I can't find out what the problem is or if it's serious.
 
Pictures:
http/i.imgur.com/5CPikiW.jpg?1
 
http/i.imgur.com/hpp59Dm.jpg?1
 
The fish swims normally and acts just like normal, my tank is a little over 6.5ft long so it's definitely big enough and It's cleaned out every Friday, I can do a water test if you need it, I didn't include one already because I didn't think it was necessary, if you need any other information let me know I'll try to get it to you ASAP.
 
Thanks for any help, really appreciated.

 

[mark4785]

To me it looks like a tumour. Tumours are primarily induced by bad water quality, other pollutants or come about naturally because of the fishes genome (it's genetic make-up).
 
To say that you are 95% sure that water quality isn't to blame because other fish are "perfectly fine" is not something I would say is the best logic to go by as the fishes age, whether it has scales or is scaleless (scaleless fish are much more sensitive to medications and toxins) and the water chemistry in which it has primarily grown up in etc are all factors that cause fish to respond at different times to inappropriate water conditions.
 
- Please can you provide your ammonia, nitrite, nitrate, PH, KH and GH levels for the aquarium water?
- What are you feeding all of your stock on a daily basis?
- How are you cleaning the aquarium? (can you detail this stage-by-stage and mention the items that you use?).

 

[Elisar]

Hey thanks for the reply.

Currently I can't do a water test because it's late here actually 4am lol but I'll definitely do 1 tomorrow, the silvers have mixed food, I don't specifically put any food in for them they just eat the food I put in for the other fish. I put in cichlid gold for my green terror and they steal some of them and I also feed them aquariun advanced nutrition, if it helps I also have clown loach which are also a sensitive fish. I've been feeding the silver dollars on this food for almost 2 years now with other food for a mixed diet, bloodworms etc.

As for how I clean it I take one piece of bogwood out and syphon 50%-70% of the water out depending on how much waste there is and how much algae I clean off. Once I've got as much waste out as possible I get an 80 litre bin and fill it with 60% hot and 40% cold which gets the temp to about 25 degrees then I add about a quarter of a teaspoon of seachem safe and I use a pump to put it back into the tank then I repeat this as many times as it takes to fill the tank, I've been doing this for two years as well so the only thing it can be is the water or like you said genetic so I'll make sure to check the water tomorrow but this is the first night it has developed because I was watching them for hours last night so I'll add more pics tomorrow if anything has changed.

 

[Elisar]

I've got an updated picture, the swelling seems to have gone down quite a lot, it was ball shaped now it's sort of like a curved triangle shape it's become quite pointed now and i'd say probably 3/4 - 1/2 the size it was last night so seems like a good sign, I don't have a GH/KH test but I do know the water in my area is generally quite soft. my neighbour has kept fish in his house for about 20 years with no problems from the water but if it still could be a problem then I can go out and get one but I've never had a problem from the water neither, as for the other water parameters, they are;
PH: 7.4
Ammonia: 0
Nitrite: 0
Nitrate: 15
 
It's not the best picture so sorry for that but I leave the lights on during the day so my clown loach can roam around as they don't like the light and I had to turn it on for this picture and when I do that the silver dollars get a little skittish for like 20 minutes or so making it quite hard to get a decent picture.
 

 

[mark4785]

How often are you taking 60-70% of the water out and replacing it?
 
If you are replacing this amount of water weekly, the KH, and GH of your aquarium water will be more or less the same as the tap water which creates no problems. If, however, you are replacing 60-70% of the water every 3-4 weeks, there will be a differentiation between the KH, GH and PH of your water at the faucet and the tank water which could cause osmotic shock to the fishes skin. If you are doing water changes infrequently (every 3-4 weeks), I would do them more frequently and do a 50% water change so the GH, KH and PH don't change so drastically.
 
Secondly, if you are adding 60% hot water you need to make sure that this thoroughly mixes with the cold water as pockets of hot water will otherwise build up and cause thermal shock to the fish.
 
I would personally test the KH and GH of your tap water and then do a test on your tank water before you have done a water change. If your tap water as, for instance, a KH level of 6dH and your tank water has a KH level of 4dH you will need to do more frequent and smaller water changes to ensure that the dH doesn't change too drastically after you've done your water change.

 

[Elisar]

Okay thanks for the help, I do 60-70% every week and yeah I do mix the hot and cold first, I believe it might just be constipation so I've fed the fish some peas today and made sure that he/she got 1 so hopefully that will help and maybe it will be back to normal by tomorrow and if not then I'll go out and buy a test. Again thank you for the help really appreciate it.

 

[mark4785]

Okay thanks for the help, I do 60-70% every week and yeah I do mix the hot and cold first, I believe it might just be constipation so I've fed the fish some peas today and made sure that he/she got 1 so hopefully that will help and maybe it will be back to normal by tomorrow and if not then I'll go out and buy a test. Again thank you for the help really appreciate it.

 
Your welcome.
 
I'd put my money on it being a tumour or abscess. The latest picture you provided of the problem gives the impression that something is erupting so hopefully anything nasty in there will be ejected.

 

[This Old Spouse]

I agree with Mark, it's not likely constipation. Hopefully it's on the mend. 

 

[Elisar]

No pictures today unfortunately as I never really had time, the lump as gotten significantly smaller though it's now about a quarter the size it was 2 days ago so I'm hoping that's a good sign and I'll update again tomorrow, but looks as if he/she's on the mend.

 

[Elisar]

Okay I managed to get some pics today and it's definitely getting smaller now.
The fish seems perfectly fine though so I'm pretty sure its nothing to worry about anymore but I'll make sure to keep monitoring it just to be sure, thanks for all the help guys, I'll update what happens in the next few days.
it's the bottom SD just in case you missed it
 
 

 

[Inspiredlynn]

I have 2 spotted silver dollars that are 16 years old. (Yup 16)! One of them has been getting the exact same lump in the exact same spot as the original post. This started after I was away for 10 days. When I returned the water quality was bad. My helper was obviously too generous with food! It is now corrected, but the fish gets this spot every other week now. He's still feisty and eats well. The lump comes to a point, then seem like it has a small hole and shrinks quickly. He has a slightly darker color than his tank mate, and has become slightly thinner. My water has been testing fine, and weekly changes are being done. I'd love for this guy to make it another year and more! Any discoveries? Ideas? P.S. I am well educated on monitoring and maintaining water conditions, so I don't need any help there. Thank you very much!