Help! Gourami's turning black

Hello fish community!
I have 4 honey gouramis that I have had for almost a year now and two are turning black. They sort of looked like they rolled around in mud, it’s covering their fins and body. One looks more black then the other but I want to make sure this doesn’t spread to any other fish!

Anyone know what it could be?

Only thing I noticed was that nitrates are at 20-30, but we are going to do water changes to get it down. We have a 55 gallon tank with some community fish like cardinals and rasboras and 3 angel fish.

What is the pH of your tank? Picture of the whole tank please?

@Essjay , you're good with gourami!
Reading the title, I thought it was going to be a male going into breeding condition and getting that stripe underneath, but from what I can make out in the photo, doesn't really look like the one we had.

@miss_monie can you try to get some more picture of the fish please? It's hard to see what's going on with just that one photo at that angle, but I can certainly see enough to understand why you're worried.

I have never seen a honey gourami like this before. Males do get black throats but not all over black. I'm afraid I have no idea why they've gone black

It is not a honey but a T.labiosa.
The black I don't know

Update! I got better pictures, it looks like his color came back a little! I also noticed another gourami is a little chunky so I’m hoping they are just mating and it’s not anything too serious! Now what do I do if they have babies?

miss_monie said:

Update! I got better pictures, it looks like his color came back a little! I also noticed another gourami is a little chunky so I’m hoping they are just mating and it’s not anything too serious! Now what do I do if they have babies?

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Disclaimer: I'm really no expert on gourami... have only had a few, and never bred, but the last male we had would develop a black breeding stripe along his underbelly, all the way up to his throat. Scared me too when I first saw it! Yours looks a little different, but I still would bet that that's the same thing. Especially since he looks otherwise healthy and well.

Look out for him making a bubble nest! Are those bubbles in the one photo him trying to make one, or bubbles from a filter or airstone?

Have no idea about what you'd do with regards to raising them - the male guards the bubble nest is all I know. What other fish are in the tank? Could make a big difference in whether the eggs or fry are likely to get eaten.

I'd personally add some floating plants for him. All of them will appreciate it since they're a top level fish, like to hide away in greenery (being at the surface with no cover leaves a fish exposed to predators - they don't know that there aren't any!) and poke about in it, looking for food and little critters. It also means he can build a bubble nest in among the plant matter and it's less likely to be damaged or blown about by the water flow.

I hope they do breed for you! And that you'll update us if they do!

Still doesn't look good actually... I recently was looking into different aquatic diseases and found a disease known as "rust disease". I forget the scientific name but some people have described it as the fish looking like they have mud or rust on them...

Here’s one more picture of the tank!
I have an air stone so I can’t tell if there are any bubble nests. There’s only one gourami that looks chunky and doesn’t have any black on them so I’m assuming it could be the female. I think some plants at the top could be helpful! Thanks for all the support! I’ll keep updates if i notice any changes.

I just looked again, and in the photo with three of them together, two of them are developing the same stripe. I missed that in the OP, thought it was just the one.

I'm even more convinced now that it is the breeding stripe, they can vary a lot in appearance. Some with just a hint along the belly, others with half their head black and a really wide stripe. So I'm gonna guess that these are fish just coming into maturity, first time breeding, and the stripe is a signal either to females about how big and strong and attractive they are, or to other males, establishing who is the best and most dominant. I bet they'll both develop and change more over the following weeks. Their stripes are either not as defined as most because they're from not great stock (sorry! Not meaning to insult your fish! and this is still only a guess), or that it will change and develop as they mature and compete.

Or, and this is my real suspicion, it's because they're a different type of gourami from typical honey gourami in stores, as @DoubleDutch said. They have a wealth of knowledge on fish, so I trust their ID skills!

DoubleDutch said:

It is not a honey but a T.labiosa.
The black I don't know

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If you google "honey gourami black stripe, you'll see how much the stripes vary, fish to fish.

When I originally googled it, my fish looked way darker than that solid black stripe so that’s why I was more concerned with it being a disease but today it’s a little more noticeable how it’s on their bellies so that give me hope! I’ll do more research on that other fish to see if it is my type of fish! Thanks again

miss_monie said:

Here’s one more picture of the tank!
I have an air stone so I can’t tell if there are any bubble nests. There’s only one gourami that looks chunky and doesn’t have any black on them so I’m assuming it could be the female. I think some plants at the top could be helpful! Thanks for all the support! I’ll keep updates if i notice any changes.

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With the angels, plus all the other fish, the eggs wouldn't stand a chance I'm afraid. If you want to breed them, you'll need to set up a breeding tank to move the breeding adults to so they can build a bubble nest, mate and lay, and the eggs not be eaten.

I don't know how most gourami breeders do it, so you'll have to go off and research!
Also bear in mind that they're thick lipped gourami and not honeys, if @DoubleDutch 's ID is correct, which it normally is.

Breeding them would definitely be a fun challenge I hope you can, and that it's successful!

Happy to help at least with the advice on floating plants! Believe me, all of the fish will appreciate it, not just the gourami, but it's also lovely to see the gourami elegantly moving around the plants and hunting for bits of food. The floating plants are also great for sucking up ammonia, so they help with water quality too. Once you've had them, you'll never go without them again! lol

Just avoid duckweed. Duckweed is evil and unkillable and messy, makes every water change and maintenance so much harder. Stick to larger floaters like Amazon Frogbit, Salvinia, red root floaters, ones like that.