Guppy fin rot

  • #1
many of you know I have a male guppy tank, only 6 males, well since adding 2 new otos ( despite quarantine period) 3 have shown signs of fin rot. I have treated tank with paraguard and have the worst guy Billym2, in hospital tank with Protozin treatment as he has white flecks too.

So far main tank, 5 guppies (3 otos, 2 armano shrimps) seem to be ok but Billym2 has holes in his tail now, he's VERY active and eating which I'm pleased about.

If you read Betta posts you will know I am from the Uk and we have different meds, I have 2 fish stores that are a great help but they aren't around 24/7 ( tut!! Great customer service! LOL)

My meds say treat 7 days but does anyone know the maximum time we should medicate a lively fish?

Also if I was to change meds in future, if I have no positive results, apart from water changes how long do you leave before treatments??

I am lucky that this is my first hosp tank job, sadly I have lost fish too soon in past.

Bm2 is in a plastic container create ( not sure of real name) on top of heater cabinet for heat with airstone from pump and a cave ornament. As I say he is still lively and his usual zippy self so if I can save/heal him then FAB!!!!

  • #2
I would change medications if nothing improves after the 7 days of treatment. Also 50% daily waterchanges on all tanks involved would be recommended.

  • #3
what are the active ingredients in those meds? I hope they'll do the trick.
  • Thread Starter
  • #4
there are no ingredients on bottle, lfs guy recommened it as has used it for over 20 years.

The little guy is full of life and signs of fungus have now gone but he has wholes in his tail.

I'm house/dog sitting for a friend for 2 weeks and so won't be home as much. I am only 20 mins away though, however I do worry! well Dave you know what I am like!!

I will look into other meds tomo if I am not too worn out! One of my buddies dogs is a teenage rottie and **** is he full of himself!! I adore him but he dosen't realise he is sooooooo huge!!!!!!!!!!
  • #5
it's a mystery to me...

i'm glad to hear of the progress and hope the fins start regrowth now.
  • #6
are guppies really sensitive so they just get fin rot?
does temperature affect the fin rot aswell?

currently I have a new guppy from a pet store and he has a torn tail maybe from the other guppies nipping him cause I saw him getting chased by the black one, he' a yellow mosaic guppy and I'm very worried about him, mosaics are my favourite guppies!I can't get a picture of him. he's swimming normaly, eating, playing with his gourami friend but he just has a torn tail.
water conditions are perfect
all the other fish are healthy

10 gallon: dwarf gourami, pearl gourami, honey gourami, guppy, four live plants, water changes every two days.


  • #7
if his tail is torn he will likely get nipped at by other fish (think open wound in the water), I would isolate him if possible for at least a week or two until you see it growing back.
  • #8
They are sensitive to fungus. Why, does your guppy have fin rot? If so I would add some salt and turn the temp up. Yes, temperature matter, a good temp. for them is 78 degrees.
  • #10
I was just wondering cause in a bad guide written six years ago says to lower the temperature and it"s not what I'm doing wrong it's the petshop guppies already having fin rot which is killing me!
I've tried multI cure cause I live in Australia and I can't find anything else
Melafix+Pimafix+salt+stress coat
Temperature always 26 degrees
I'm quite stuffed trying to treat the troubles from petshops, can you believe when they netted my fish they dropped it on the carpet!I nearly killed him for that!and all the fishe's fins just get white stuff on their fins, I don't really know if it is fin rot because the tail starts to look likes it's peeling from the center?Whitish stuff peeling but I don't see anything missing just peeling and dying guppies!

likely he just got nipped but it's quite disturbing to see I'm having a war against fin rot with no success so far, well the guppy is fine but my old ones looked like the tail was peeling with white stuff from the center and it was my favourite black snakeskin so it was really obvious. They just die for no reason! Sigh!:'(


  • #11

I'm sorry to hear that you are losing fish. I recommend not buying fish that you know are diseased. I would have refused the one they dropped onto the carpet.

Quarantine...I highly recommend it for all new fish before going into your main tanks. It may save you a lot of heartache.

Hold on for more responses.

  • #12
I've stopped buying guppies from that store
The only reason grrrrrrr I bought that guppy was the guy simply didn't want the fish back in the sale tank, I was saying " He's hurt!" And the guy was saying" He's fine!" and he got a mate to convince me! Goodness! Two people saying he's fine at the same time!The store gives terrible advice!All their other fish are good there and I usually get my fish there and they were all fine except the guppies. I'm sad to say their guppies get worse and worse! :'(
I saw them put a bleeding heart tetra in there and it bit off half of a pretty guppy's tail
John Hutch
  • #13
HI masaicguppy,

Ok you have a tail rot issue right? I have had a battle as well with it in my 30 gallon tank with my Bumble Bee Platy. I used salt and an Ich product (recommendation) to no avail. So I went and bought Maracyn II and now it has stopped spreading and its beggining to heal.

If you decide to add any more meds of any kind do a water change first.

Good Luck
  • #14
I've checked lot's of petshops but all they have is melafix!
sure it helps the healing but not the actual fin rot!
But sadly my guppy died!:'(


John Hutch
  • #15
I am so sorry to hear that. I don't like posting online sites I purchase from but if you check out you will find medicines that Local Pet Stores don't carry anymore. Check them out. Their prices as far as I am concerned are the best.

Oh a good med to have on hand to handle an array of bacterial and fungus infections that has worked wonders for me is Jungle Fungus Eliminator. Even takes care of fin rot in no time.

Good Luck
  • #16
Oh! Wait a minute! One more petshop I haven't checked!
But I'm giving up on guppies anyway, I loved my little guy!:'( I find it weird that my gouramis don't get anything? It's only the guppies but might be a bad stock.
  • #17
Hey everyone,
Its been a little over two weeks since my last post about moving my fish. I have three guppies in a 20 gallon and a platy in a hospital tank which I am treating with seachem's paraguard (I believe is quite awesome) with velvet (I think its all gone ).

My platy (name is Messi), I plan to leave in hospital for an extra week to be sure all of the parasite is gone.

My issues are my guppies now. So when I moved to my new apartment two weeks ago I dosed my 20 gallon with Tetra Safestart. I haven't done anything to the tank since then. My tank is cycled and I believe actually cycled within 3-4 days (I obtained filter media from an established 55 gallon along with the TSS).

I just checked my tank parameters: (using API master kit)
ammonia 0
nitrite 0
nitrate a little over 20, (can't really tell slight red tint to brown)
PH 7.4-7.6
temp 78
I also do use aquarium salt (I know some people don't like it)
moss ball in tank as well

My guppies have appeared to have issues with their fins (tail fins mostly). They appear to look clear near fin edges. They looked like this since I moved them (my memory is awful, but I believe at one point they were full of color when I first got them a couple of months ago)

I have a picture of what I am talking about.

2014-01-22 20.49.43.jpg
2014-01-22 20.52.36.jpg

I am not sure if this is fin rot or possibly guppy aggression (stress). Reason I say this is because all three are males and they are constantly chasing each other. My black (or blue not sure what color he really is) guppy (name is Francesco) also actually has become territorial and tries to peck at the others when they come close to this hut ornament I have in the tank. But their tail fins have looked liked this since I have moved them to 20 gallon (and even before). This morning my yellow guppy has a rip in tail fin (in the picture).


My tuxedo guppy's (name is doodles, I know, sister named him) tail fin had a small rip a couple of days ago but it was together the next day. But in the photo my yellow guppy (name is snoopy) tail fin has a quite large rip. I don't want it to get worse. I have stress coat (normally I use prime for conditioner), which has that aloe vera, and I am probably due a small water change maybe (10-20%). I am not sure whether I should just do a small water change with stress coat or maybe treat with meds. I have melafix and pimafix, but I am losing faith on these products. Last time I treated with these my cycle crashed and I am not sure whether I should use them or perhaps I should incorporate a water change in the middle of the treatment (seven days) to somewhat keep the concentration in check.

My little guys seem happy swimming everywhere except they chase each other every once in a while, and I just want to prevent anything from getting worse.

Any advice I would greatly appreciate.
Thank you Fishlore Community! (everyone has been so helpful since I have joined)
  • #18
Why are you using salt in a freshwater tank? It's easy to raise the salinity level too high for the species you have and your particular species don't require, or like, salt at all. I would do a couple of back-to-back water changes (50%) to get the salt out of there.

That's not fin nipping, definitely. That's stress.


  • #19
Thank you for your response. So you think the aquarium salt in the water is stressing them out. I only added it When I set up the tank two weeks ago and added to measured amount of water with directions on the box? I am just a confused about it cause I read on other sources that guppies do well with aquarium salt but if that's the problem I will remove it
  • #20
I would absolutely remove it. Guppies do not require it.
  • #21
Thank you LyndaB for the advice.

I was planning to do a small water change today, but now after your advice I will do a 50% without any aquarium salt. I have question about the back to back water changes, since they are stressed already wouldn't back to back changes stress them out more?

I hope this will help them in reaching peak health. I figured the discoloration in the fins (clearness) was stress, but I wouldn't have thought of the aquarium salt. I thought all this time it was the fact they chase each other every now and then.
  • #22
For fin damage, pristine water is your best medicine. They will not get stressed by cleaner water or by the water changes.


  • #23
Thanks again LyndaB!
I have noticed a significant amount of water loss in the tank due to evaporation. The salt concentration may have risen due to less volume in the tank as well.
  • #24
You're welcome. Keep us posted!
  • #25
Adding salt is sort of an old time cure all, sort of in the manner of bleeding people was once thought helpful (and it is, but only very rarely, as in relieving pressure on a specific organ, to a specific aim).
Having said all that, perhaps your guppies could benefit from adding more female guppies?
I am not at all an expert in livebearers, other than my wife, but many fish live well in a 1:3 male female ratio.
I, myself, prefer a 1:1 ratio, but allow my Rift Valley cichlids the 1:3 ratio, and it seems to work quite well.--rick
  • #26
dont look down upon salt in a guppy tank. with the right amount it is more benifical than not using it. salinity increases slime coat production. it also inhibits bacterial growth rate.

just keep doing your weekly water change and watch it over time. if fins starts fraying then it most likely is fin rot.


  • #27
Adding salt is sort of an old time cure all, sort of in the manner of bleeding people was once thought helpful (and it is, but only very rarely, as in relieving pressure on a specific organ, to a specific aim).
Having said all that, perhaps your guppies could benefit from adding more female guppies?
I am not at all an expert in livebearers, other than my wife, but many fish live well in a 1:3 male female ratio.
I, myself, prefer a 1:1 ratio, but allow my Rift Valley cichlids the 1:3 ratio, and it seems to work quite well.--rick

I thought of adding females, but I don't think I am seasoned enough to deal with fry. And I really don't like the idea of just leaving the fry to be eaten by the adults as well.
Thanks for the suggestion thought.
  • #28
When I added 6 male guppies 1 of their tails ripped, I thought it was aggression, since guppies are fin nippers. I didn't change anything and it healed on its own.
  • #29
dont look down upon salt in a guppy tank. with the right amount it is more benifical than not using it. salinity increases slime coat production. it also inhibits bacterial growth rate.

just keep doing your weekly water change and watch it over time. if fins starts fraying then it most likely is fin rot.

This is what I thought as well as I have seen on other sources that they would thrive in aquarium salt. Perhaps I added too much. I have seen conflicting reports some say teaspoon per gallon or tablespoon per 5 gallon.

When I initially setup the tank two weeks ago, I did the tablespoon per 5 gallons. I thought this was fine, perhaps it is not.

I just now did the 50% water change as well without any salt (to lower salt content if it was too high). Like I mentioned earlier I noticed a significant water loss due to evaporation. I took out about 6 gallons and put back in about 8 gallons, so I lost two gallons due to evaporation. I am not sure whether I want to do a back to back water changes. I had to move in an emergency and this tank had water from my old place (in a previous post), so I haven't gotten my fish use to the water in my new place as this was the first water change since setting it up.

I thought of the possibility of it just being fin rot, and I have melafix and pimafix. However, last time I treated with these my cycle crashed and I don't want to go through that again. I also have seachem's paraguard, which according to seachem is a broad spectrum cure, basically any external infections (bacterial, fungal, parasitic). I didn't really want to treat my main tank, but my platy is recovering from velvet and I didn't want to put any of the guppies in the hospital tank with him.

I am not sure if it comes to treatment I should just use paraguard, basically you dose it everyday because it evaporates from the tank in a day. As soon as symptoms disappear you quite dosing. On the bottle it says it can treat fin rot as well, or anyone has any recommendations for treatment if it comes to that.

Again thank you all for the info!
  • #30
You don't need meds for this. Just do the water changes. You should see results within a week. It could very well be that your fish are slightly stressed from the different water. That said, if you're using the same dechlorinator, you should be good.

I still stand by my opinion that freshwater fish do not require and, in some cases, cannot handle having salt in their tank. I've heard the school of thought that a little salt helps, but frankly, there are very few members in this forum who attend that school.


  • #31
LyndaB I think you have a point about the salt. They don't require it, and since I have been using it their fins (all three guppies are showing the clear edges on their fins) ,just my yellow guy is the worst. The other two guys sometimes both chase him together. I just hope they aren't stressing him out too much.

My tuxedo guy had a slight rip the other day in a similar place but the next day it was fine again.

The water that was in the tank had water from my old place, they aren't use to the water I just used right now in the first water change of that tank. I am just worried about changing the water composition too fast on them. The water should be the same as my old place since I just moved into a different building on the same apartment property, but I want to make sure.

Another thing I notice on them is discoloration along their backs. Tuxedo guy looks like he had the most, but I'm not sure whether that is just something that the yellow pigment of these fish have. Tuxedo is blue yellow and orange, and the other is completely yellow (shown in pics)
  • #32
then again mollys, gobies and puffers are brackish, yet people throw them in freshwater. so you should not use salt since schooling says so
  • #33
Hey everyone
I just checked on fish. The split in my guys tail fin is gone. It looks like his fin came back together. Still there like the discoloration like I shown in the pictures before on the fin edges
  • #34
It's amazing what the clean water can do for their finnage. Glad to hear they're getting better.


  • #35
Thanks LyndaB.
I just hope the color in their fins comes back along the edges. I read somewhere that the discoloured fin edges could be fins regrowing and it could take weeks for the color to completely come back. I'm am not entirely sure??
  • #36
Is your tank new by chance? Is it only happening to the males? Let me know.
  • #37
Worried about guppies!

Hey everyone,
Just updating about my guppy situation. My yellow guy's tail fin has came back together, but his tail fin is still clear around the edges (has been like this too). I am beginning to worry about my guys.

My yellow guy has clear edges on his tail fins. My black (or dark blue, not sure exactly) guppy appears to have ragged places on his tail fin, but I am not sure whether they are bites from the others or my first suspect of fin rot. My tuxedo guy also has clear edges on his tail fin too, but no where near as much as the yellow guppy.

Other things that kinda have me worried are the colors of certain spots on my guppies. Most noticeable is my tuxedo guy he has areas that appear to have no pigment (white). I am not sure whether I should worry or it is something like fungus or columnaris (hope not). His scales are also not as smooth as my other guys and I am not sure whether that is something that could happen since he appears a bit chunky (fat, not bloated) or worse like dropsy (I really hope not, he doesn't look the pine cone in pictures I have seen). He has been like this for a while several weeks I believe. Also I have recently upgraded their food to omega one (color enhancing) and spirulina flakes, and it looks like the areas that look like that have no pigment on the top of his tail before you reach the fin has gotten the color of that area, but you can still see where the difference is. This is what kinda leads me to the idea that maybe just areas with not much pigment, but I am not sure.

My other concern is my black guppy, he has had a black spot on top of his head. It doesn't look like a lump or anything on his body, but just a spot that has a color of black. I am not sure whether this is something or not.

I am uploading several videos of my guys. I know they are somewhat long (almost 3 minutes each), but I would appreciate it if you all could please take a look at them.

I thank you all for your help.
  • #38
Hey everybody
I believe my guppy has fin rot, it developed overnight I'm pretty sure because his rail was fine yesterday. I noticed a few days ago he seemed paler than usual but I wasn't sure why, now I'm pretty sure it's this.
Do I move him to quarantine now?
How do I treat for it?
Do I need to treat my main tank as well?
I'm worried and hoping everything turns out ok!!
My water parameters are 0 ammonia, 0 nitrite, 5 nitrate and ph is between 7.4 and 7.6 not sure which according to the colour it turns.


  • #39
Pristine water conditions will work. Daily wc depending on severity.
Id make sure it's not nipping.
  • #40
It could be nipping, but I've had them all for 4 months without issues and now his tail has a large chunk missing from the middles and all the edges are frayed. I've set up a quarantine tank with gravel from my tank and the filter is loaded with media from my bigger tank, I've also done half cycled tank water ( from the 45g) and then added fresh water the rest of the way. I'm going to test the parameters of both my tanks before feeding time and do the switch if they match.

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