Really Worried? Fin Rot?

Woke up this morning to find all of my of my five guppies except two have got torn sort of ripped tail fins. At first I thought maybe they had just been fighting however when I looked at my platies I saw that one of them has a little tear at the side of his tail fin aswell, so I thought just to be on the safe side I would check my catfish (who is temporary been living with the guppies and platies) we also has a small piece missing in the middle. Really worried as I hope its not fin rot I keep my tank clean, have always done weekly cleans except the last one had to be left for 3 weeks but was cleaned on saturday and wasn't very dirty at all, the water wasn't even cloudy. I never overfeed (often i think i underfeed ) I feed once every other day, a pinch of fish flakes and one algae wafer, I have 5 guppies, 2 platies and one peppered corydora (soon will be living with more again) Does anyone know what it could be? Is it likely that there was a fight or is it fin rot? Please help, I am really worried about them

A pic would be helpful, if you can.

A picture would help. Do the missing parts look like it was ripped at all? Do they show any signs of stress (ex. Panting or breathing rapidly, staying in one spot)?

They look ripped yes Malex530, I can't upload a photo as my phone broke at the weekend and I haven't managed to get it fixed yet, but when I do I will upload one. This morning when I put the light on, the one guppy was on the gravel looking a bit sleepy, sometimes they do as I wake up at 6 and they are often still sleeping and then the light shocks them but they soon start swimming again. I am really worried but I found some disease clear in the cuboard I added some to the water and it said it is for fin rot, mouth rot, itch, swim bladder and any bacterial diseases, hopefully that will help. Fingers crossed, I cleaned them out yesterday aswell, I have tried doing everything I can think of Is there anything else I can do to help them? Thank you so much for your help 

It does sound like a fight, but all the inhabitants have it correct? 25% water changes every other day unless dosing medication.  

Yes all guppies except one have and both my platies and my catfish. I have put in a dose of medication this morning and the bottle says to do another dose in 3 to 4 days so I will do another on friday, I also did a 25% water change this morning before giving the medicine Really love these fish, I previously had 2 platies, one german blue ram and a gourami but sadly all die except my catfish (whom I am now attached to after nursing him back to health I think they were poisned as I had being putting perfume on in my room, with my fish in I have been taking extremely cautious care and done my very best for these new fish and if they die I think I would have to give up fish keeping for a while its too upsetting when they die and you have tried everything you can Really hope these guys pull through, really dont know what could of caused it though

Got these pictures on my mums phone early this morning, they are a little worse now, hopefully you can see the ripped tail fins.

Just went upstairs to check on the fish and the red guppy, who looks like he has a sort of red leopard print like pattern, he was lay on the gravel breathing very fast. I took the lid off to move some of the plant out the way so I could see the fish and the fish jumped up and swam off like normal He then joined his friends and swam perfectly normally with them, can't work out whats going on he is usually the one who does the picking on the others so I don't think he is being picked on or anything like that really worried about little Lenny

i had issues with fin rot recently. how are they looking today? its weird for so many fish to get it at once in my experience unless your water is REALLY bad. tends to be a couple when ive had it. can you see any inflammation/redness at the base of any damaged fins and/or any fine white edging to fins? its hard to see from your photos but what is the damage like? a frayed/jagged receding fin all along the span (more likely rot)? or sometimes when they nip each other you can literally distinguish mouth-shaped bites
 
also are you able to test the water parameters? the rapidly breathing guppy is most likely stressed which could be caused by fighting or poor water so best to try rule stuff out asap

They all look a lot better today, all swimming normally. I do clean the tank once a week with a gravel cleaner and a 50% water change except last time when I had to leave it for 3 weeks but the water wasn't that dirty or anything Their fins have got a jagged sort of frayed edge all the way along the fin but their is defiantly no reddness and I can't see any white on them either I can't test the water today but I could take it to the lfs and they would test it for free. Think I will do that tomorrow

mmkay well sounds like your maintenance is good. why do you choose to do 50% each week though? is your tank heavily stocked? i tend to do 10-20% weekly and that is sufficient in keeping nitrates down. more than that and you can start to alter water chemistry more dramatically (esp if you have driftwood etc softening your water between changes) which can stress fish. do you ensure the added water is the same temp as tank water as well?
 
also while the clarity of the water is important it is the invisible constituents which are the main problems. ammonia, nitrite and nitrate will have no visible indication except for causing stressed fish so id really recommend buying a test kit to monitor these at least weekly. API freshwater master test kit is considered the best all around; just make sure its the liquid one and not test strips. you can get one for around GBP£20 these days and its honestly one of the best investments you can make in the hobby as testing the water at the first signs of trouble can go a long way to helping diagnosis and treatment. not only that but you can monitor and provide the best quality water for your fish which equals happier and more colourful/lively fish all around.
 
the fact there is no redness or white edging is a positive sign as one or both of those symptoms tends to materialise with fin rot. id say keep a good eye on it now and let us know if you notice any.
 
best course of action for now would be to keep doing 25-50% every other day water changes with dechlorinated and temp balanced water and monitor the fish closely. a load of fresh water can go along way to helping stressed and sick fish recover on their own
 
good luck!

Well i clean my tank out weekly, It's usually a 25%-50% water change depending how much cleaning the gravel needs. My tank isn't heavily stocked, 5 guppies and 2 platies. I have no driftwood. I always make sure the added water is the same temperature as the tank water,I often stand for ages with one hand in the tank and the other in the bucket haha. Ok so I think I will do a 25% water change tomorrow. This morning they all seemed a little better but whilst I was at school mum said two of the guppies were swimming sidewards anyone know what could be going on with them? 

My fish still aren't much better On sunday 2 of my guppies were swimming sideways, so I went to a very good petshop which took me about 1 hour to get there but they gave me some great advice! On monday I did a 50% water change and then added so very strong fin rot treatment which needs to be added weekly and I am going to carry on with the 20% water changes once a week. Their fins dont look much better but the red line around the torn part of the fin has gone and they seem a lot perkier fingers crossed