Harlequin Rasboras Color Change

Hello all. I have some Harlequin Rasboras and I am wondering something. What does it mean when the black patch on the tail fades? The black is not completely gone, it's more of a grey color than black. They seem to be doing well; eating properly, swimming normally, shoaling at times and moving about independently at other times. All in all, normal behavior. (As one can see from my spelling, I am from the USA, so please bear with me  ) Should I be concerned or is the color change normal? Do I need to change their food or anything else for that matter?

My other Rasboras haven't experienced any changes that I can tell. I feel that this forum is one of the best sources for answers as I cannot seem to find any from other sources I've tried, so I'm relying on you good folks. Please help, if you can.

Hi there and welcome to the forum 

If you could post some pictures of your fish that would also be helpful.

Welcome to the forum and thanks for the complimentary words re it too.

I'm assuming you mean the black "pork chop" shape on the flank and leading into the caudal peduncle area? Could you tell us a bit more about your tank, its inhabitants and your feeding/water change regime [eg how old are the fish, how many of them are there, what other fish are in the tank, what size is the tank, what decor do you have, what is the water quality (ammonia, nitrite, nitrate readings) pre- a scheduled water change?], so that we can get a better idea of why their patches are fading?

Potential possibilities might be a deterioration in water quality such as through insufficient water changes (and it's possible that long-term exposure to even small amounts of ammonia/nitrite or high nitrates may be manifesting itself in this way), a change lately such as a change in decor or a brighter light tube fitting which they may not like or which may make their black patches look paler, food having gone past its shelf life (even if still within the best before / use by date, it may have been open for a long time and deteriorated in quality) or the brand or variety not quite being optimum for the fish, tankmates dying off or new tankmates bullying (some species of fish are fine as juveniles but change as they get older), but there may be other reasons.

Hoping these help as a trigger for thought and maybe if you answer the questions above (sorry for so many!), it may help shed us light on what the problem might be.
 

Thank you for the welcome.

Yes, I mean the "pork chop" markings. My tank is a 75 gallon tank. the inhabitants are as follows: an 18 inch Plecostomus (7 years old), 4 Harlequin Rasboras (4 mos. old), 4 male Fantail Guppies (also 4 mos. old), 8 Corydoras (5 also 4 mos. old and 3 between 2 weeks and 1 month old).

There's a large dragon that has an air line in it, a rock cave formation about 4" high by 10" long by 6" wide for decoration and 4 Anubias and a couple of ferns for live plants. The plants are sparse and I need to add more. The substrate is black and white sand (National Geographic brand). I do a 20% water change at least bi-weekly. if not weekly the water temp is kept around 76 degrees F.
I really haven't checked on the pH of the water, so I can't supply that information.

The food is fresh and was sealed when I first opened it. I usually give a pinch twice a day, but sometimes miss an evening feeding about once a week. The food is National Geographic brand Tropical Energy Flakes and Tetra brand Pro Cory Wafers. I feed the Plecostomus a quarter of a zucchini once a week. He usually takes two days to eat it.

Last week we relocated our household including the aquarium. i know this had to have stressed our fish, but I tried to make it as smooth and easy a transition as I could. I made certain that the fish were acclimated to the new water and brought their water temperature to the same temperature as the tank before reintroducing the fish: the usual treatment for introducing new fish.

The color change has nothing to do with the relocation, though, because it occurred about a month prior to the move. The other Harlequin Rasboras have not shown the same change. All of the tankmates, as you are aware, are peaceful. the Plecosotmus doesn't bother any of them even though he's like a ship amongst canoes. The Corys actually feed next to him as though he is a decoration.

I'll attempt to send pictures in a subsequent post.

Stan

I have increased the number of Rasboras to 8, checked the pH and regulated it to 7.0, added 2 more guppies, 2 Panda Platies and some Neon Tetras. 4 out of 6 of the Neons died in less than 24 hours, 2 before getting them home.

We have decided that our Pleco, Drac, will have to be adopted out of our tank. By his size alone, he has become like a bull in a china shop and he is trying to get under a structure that is too small for him. He pushes so hard that he displaces the sand and uproots the plants.

I am still trying to get Water Sprite plants locally, but may have to buy them online.

The scheduled water change is getting done today. I'll likely do a filter change in two days as well, after the water clears from the water change.

While I'm reporting all of these improvements and changes, no changes have occurred to my Rasboras. they still look paler than when I bought them.

I replace my debris filters and leave my biofilters alone. i do have some experience with that. my new Rasboras are not faded.