Frontosa Fins Shredded…Aggression or Mating?

[MisplacedTexan]

I picked up a group of 5 Adult Kigoma Frontosa in early August.  The largest is about as big as my hand finger tips to wrist (~7in), with the smallest being palm sized (~4in).  They are in a 180 gallon tank with weekly water changes, Temp 80F, 8.2 PH, Hardness 250-300, Nitrite and Nitrate perfect with a sump that turns over 8 to 10x the volume per hour.  Tankmates of a sailfin pleco, 5 syno cats, and 4 anubias plants.  The Fronts are eating well and coloring up nicely.

BUT about 3 weeks ago I started to notice white blotches on the pectoral fins of the 4 smaller fish.  Looked around online and after ruling out common suspects (Finrot, Fungus, etc) it looked to be like more along of the lines of a trauma/bruise. None of the other fins or fish showed any signs of distress and no other symptoms appeared. Hoped with regular maintenance the fins would heal.  I even went as far as adding a constant water change / drip system to improve the water quality.  But that didn't help and eventually the largest also started getting marks on this fins as well. I continued to monitor and hoped it would clear up… but in the past few days it has gotten much worse.  The smallest fish had it’s pectoral fin on one side completely shredded and was moved to medic tank.  This literally happened over night and I can only assume it is caused by another fish.

Since the tank mates are relatively docile, it must be one of the group. The question then is… do I have 1 or more sub dominate males being picked on? Two males fighting for a mate? Or is this type of aggression common place when mating? 

I tried venting the 4 smaller ones but it’s not a clear cut as the pictures online show.  I think the one with the badly torn fin is a male and was possibly bullied… but not sure?  Even at 4 inches its hard for me to know what I am looking at... ( keep your minds out of the gutter) Anyways if someone is more familiar with venting, especially Fronts, I would really like a second opinion… PM me and I can email or text pictures I took.

Anyone seen this behavior before in Frontosa?  Any other opinions on what might have caused this or things to check?   If it turns out I have multiple males what options do I have to curb the aggression?  Add more Females? Sell off the Males? Turn down the temp?

TIA

[Steve]

Haven't seen much aggression with my fronts like that. I have 125g with three male fronts from 9"-12" and then one female 9",  and 5 unknown sex 4"-5". I keep my temp at 80F as well. How big is the sailfin pleco? Could by chance he be chewing on some fins during the night? I just had to get rid of a couple of my plecos recently because they started chewing on my 5" albino Oscar while he slept at night. Started seeing shredded fins on him as well as spots on his side and found it was because of my plecos. Maybe check during the night a few times over the new few nights and see is you find anything like that happening. Not sure if the Synos may could do that as well because I never have kept them with my fronts.

It it is aggression in the group of fronts themselves then what sort of decor/setup do you have in the tank? Even as male heavy as I am with some real big guys my aggression is almost zero but I have numerous rocks and tree branches to help break up sight lines and such.

[MisplacedTexan]

The main decorations in the tank is a crescent shaped stacking of smooth rocks takes up middle 1/3 of tank, about 10-12" high.  Lots of little holes for the syno cats.  On the ends I have drift wood. One piece is a single branch laid over, and the other is a small hollow stump.   Nothing I would suspect would be able to shred fins.  This lay out has a few visual  breaks / turning points to break up the occasional chase.



The Sailfin Pleco is only a year old, but already close to a foot long.  During the day it hides under the driftwood. I drop in a few algae wafers at night for him and based on the fat tummy and amount of poop he makes I assumed he is fat an happy.  Once the smaller Front's fins looks to be on the mend I will scoop out the Pleco and drop him in solitary confinement for a while.  If the fins improve then I can look into rehoming the Pleco I guess.

[cranialdisturbance]

I had a group of Kigoma Frontosa and they were kept in similar conditions.  I did not have problems with aggression.  The main damage to any of my Frontosa was of the self inflicted variety.  Usually becoming startled and darting into a rock or crashing into the glass top.  Unless you have witnessed them fighting and doing actual damage to each other I would suspect the much larger pleco of being opportunistic at night.  Find somewhere else for your pleco to live and maybe get some bristlenose plecos that won't get so large.