black patches/ mark on active fish

jhw1126

Feeder Fish
MFK Member
May 9, 2019
22
17
8
27
African cichlids tank
Tank size: 120g
water parameters:
ammonia 0ppm
nitrite 0ppm
nitrate 20ppm
PH 7.8
test kit: API freshwater master

the system is been up for 6 months now

the tank currently has:

RedFin Kandango x2 (1 male 1 female) 4''
Red Empress x2 male 5''
Venustus Cichlid x3 (1 male 2 female) 4''

Deep Water Hap x2 male 6''
Blue Dolphin x2 4''
Electric Blue Hap x2 male 4-5''
Star Sapphire Cichlids x13 3''

Mbuna
Blue Lip Williamsi x2 (1 male 1 female) 7''

Peacock
Sulfur Head Cichlid x1 male 7''
UNDU POINT Blue Neon peacock x5 male 2''

TOTAl: 34 inhabitants

besides the blue neon(quarantined) i got from 1 month ago, the rest is well past 3 months
no aggression issues, i removed all bullies whatever is left in tank are all very peaceful, tank boss is the blue lip Williamsi, which only stays around their cave

Temperature: 80~80.5F, 0.5F swing due to hardware limitation
the system runs on a custom sump and an fx6, plus a jebao cp120 on 40% capacity. oxygen is not an issues
auto water change about 1~1.5 gallon every hour
sump and fx6 gets clean every month, 2 weeks in between each filter


the two 200w heaters are from aqua top titanium heater, controlled by a inkbrid aquarium controller(submersible probe ), the system has a ground probe installed.

ruing turbo twist 6x feeds by a 172gph pump, after headpresurres its running about 100gph, which should kill everything

no natural sunlight, lighting is from 10 am-11:30 pm with a Fluval marine 3.0 on 5~10% capacity

i feed 2 times during weekday, once on the weekend, i rotates between Hikari sinking excel, Northfin cichlids formula and tropical Malawi chips.


UNUSUAL SIGN: Balck patches/ marks
There are one red empress and one electric blue Ali showing these patches and mark and it seems like the patch seems like it is getting bigger as the fish develop more colour and grow larger, they eat and act just fine, very active no flashing behaviour (image attached)

all others are doing fine maybe a bit fat but no sign of sickness and similar marks

can someone please tell me, what could those patches/ marks are
it is very disturbing for me to look at it
any educated guess are also welcome, thanks
WeChat Photo Editor_20191215232404.jpgWeChat Photo Editor_20191215232425.jpg

WeChat Photo Editor_20191215232439.jpg
 

kno4te

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Dec 24, 2005
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Guessing just some coloring on the fish. Doesn’t look like an obvious infection.
 
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duanes

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Isla Taboga Panama via Milwaukee
I agree with Kno4te.
One thing I would add though, while the surface temp of Lake Malawi will seasonally get to 84'F, the average temp at depth where cichlids live is much cooler, @ in the mid 70s'F.
So your over 80'f temp might help certain bacterial infections become problematic.
 
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