Why Does My Platy Have A Red Belly?

Platies first.

Do you know if you have males or females? If you don't know, the way to tell is by the anal fin. That's the one on the underside just in front of the tail. Have a look at the photo in the fish profile here. There are five fish in the photo. The two at the bottom (yellow on left, red on right) are females. Their anal fins are the normal fan shape you'd expect of a fin. The other three are males. Their anal fins are not fan shaped, but rod shaped. This is called a gonopodium. You can see it best through the panel of writing on the red and black fish top left.
Male livebearers like platies chase females constantly. It is recommended to have at least twice as many females as males so that each female gets time off while the males chase another one.

A red underbelly could be a pregnant female. In this case the red would be above the anal fin where the babies grow. But if it is a male it could be a sign of something wrong. If it looks fat, look down on it from above (I know that won't be easy with the narrow opening of the biorb). Do the scales lie flat against the body or do they stick out like a pine cone?


Now the cycling. With ammonia and nitrites at 2 in the biorb, you need to be doing water changes to reduce the level. Change most of the water; leave just enough for the fish to be able to swim in then fill back up with dechlorinated water at the same temperature as the water you took out. Warm it with hot tap water if you have a combi boiler or with hot water from the kettle if you don't. Then do water changes as often as necessary to stop either of them getting above 0.25.
The betta's tank - the ammonia is a bit high. It will be OK as long as your pH is 7.5 or less. But again, water changes will lower it.

Don't worry about the pH for now. Treating the whitespot and keeping the ammonia and nitrite under control is more important. Just to check, did the betta look as though he had salt grains on him? And since you've had to remove some filter media (carbon) you will also have removed some bacteria so monitoring those levels is now quite important.
Is there anything in that tank that could be increasing the pH, other than the whitespot treatment? Anything such as shells, limestone rock, coral?

You do need to do more water changes on the biorb, I'm afraid. Nitrite at 2.0 is still way above the danger level of 0.25. Even a 90% change will only get that down to the upper safe-ish limit.
I've just noticed that in your first post you mention having a biorb and then a heated 22 litre tank for the betta. Is the biorb heated? If it isn't, that explains the slow cycling as the filter bacteria grow better at higher temperatures. And you will probably need a heater in winter unless you can guarantee the room never drops below 18 deg C on the coldest night.

The danio is probably stressed because they are shoaling fish and it is alone. But it is not a good idea to get more while the tank is cycling. More fish means more ammonia made even faster, and converted to more nitrite.

Water changes do not harm the bacteria unless you forget to dechorinate the water, and even then when the colonies are mature that does little harm. It's when the colonies are first growing, like yours, that you have to be sure to use dechlorinator. Though the fish don't like chlorine much either.
The filter bacteria grow tightly bound to the biofilm. The biofilm is tightly bound to all the surfaces in the tank. The bacteria prefer to grow in the biofilm on the filter media as that has the best water flow though it bringing food and oxygen. In most filters, the media is also in the dark which the bacteria prefer, though with the biorb's biomedia being the substrate that doesn't apply in this case. It is not easy to dislodge the biofilm, though hard scrubbing of things like filter sponges can do so, especially with immature media. With the biorb's  bacteria being on the substrate, you'd have to really scrape it hard to dislodge the biofilm.

As long as the new water is dechlorinated (to protect the bacteria and the fish) and warmed to the same temp as the tank (so as not to shock the fish) it is safe to do a 95% water change. That's just about as much water as you can get out while still leaving enough to cover the fish.


Whitespot will disappear from the fish but it doesn't mean it has gone from the tank. It is a parasite with a three stage life cycle. We first see it as the white spots on the fish. It is attached to the fish inside a coating, and feeds off the fish's skin. It is on the fish for a few days before each parasite grows big enough to see. The coating protects the parasite and medication can't get at it. Once the parasite has eaten enough, it falls off the fish and lies on the bottom of the tank, still in its coating, and multiplies. The medication still can't get at it in stage 2. Finally, the coating splits open and releases free swimming baby parasites which set off looking for a fish to infect. Stage 3 is the only one where the medication can get at the parasite.
There will be some of each stage in the tank at any one time. It is important to keep adding the medication as the instructions say to make sure there is some medication there when every last one gets to stage 3. If the instructions say to turn the heater up, that's because this lifecycle goes faster in warmer water.
If you need to do a water change on non-dose days, add the amount of med needed to treat the volume of the new water you put back in to replace the amount you've taken out.


I've heard that comment about biorbs before    They can be nice tanks as long as you are prepared to work with their limitations.

are you sure it was dead shrimp and not just a molt from a shrimp they can look the same sometimes mine very often scare me with that little trick as for the white spot i am not to sure but i think that if blood worm could cause white spot its more likely to be live blood worm not the frozen version , i feed mine frozen blood worm often and its been ok they soon eat it all up 

It's totally impossible for bloodworm to cause whitespot. To make it possible to produce enough bloodworm to sell, they have to be bred in special pools where, of course, there are no fish since fish would a) eat the bloodworms and b) die from the low oxygen conditions in which blood worm thrive. Since whitespot can only be present where there are fish, clearly it cannot be introduced with bloodworms. Just another loony idea circulating among fish keepers.

I think it's vital to always remember that fish diseases come from other fish. Yes, there are also dangerous physiological conditions that can be caused by poor water quality, but any true disease caused by bacteria, fungi, protozoa, parasites or whatever ultimately has to come from another fish. That's why introducing new fish to a tank is a much more risky procedure than one may think, and why so many of the "Help!" questions here often arise shortly after the introduction of new fish. Sometimes the new fish get sick/die, sometimes it's the ones already in the tank which may have no resistance to a newly introduced disease. Very close observation of your fish after new introductions is essential if quarantine isn't possible. It's also important to take remedial action as soon as possible, by the time a fish is on its last legs (last fins, perhaps?) it may have already infected all of your other fish. Even more so if you leave it to die and the others start to eat it...........
We shouldn't always blame the shop either, because their fish may appear perfectly healthy to them but have a low level infection of whitespot, for example, which might only appear later as a result of the stress of moving into new conditions in your tank.

This fish-keeping is a very steep learning curve. We've all been there and made similar mistakes (even Sue *sharp-intake-of-breath*) but we've all been willing to learn from them. It'll be fine in the end..... but it does seem to take six-months or so to settle down. Stick with it - it's worth it. I've just spent the last hour or so sitting with a glass of wine (or two) and watching my tank. It's great once it all comes together - it really is.

I just typed an essay and lost the whole lot? So in brief:

Colin B - I'll be on the sofa tonight enjoying my little fishies with a glass or 2 of wine (most welcome after last night's drama)

Sue - Guess what?:

AMMONIA - 0
NITRITES - 0
NITRATES - 0

I'll be testing every day and am not scared to go in with the big guns now if I need to - 95% water changes? Pah, piece of cake!

Kai (betta) has had his 2nd dose of meds and (apart from swimming around in electric blue water) looks ok. I think I saw another couple of white salt/sugar grains on him before I dosed the tank but could just be being neurotic.

They're all going to get a nice bloodworm breakfast in the morning too now that I know the frozen stuff is fine for them.

Thank you so much for your help. I'm sure I'll be back on here soon with yet more questions and will keep visiting too as I like reading all the posts from other people.

Oh and Sue - sorry to hear about your disasters...if you need any advice just let me know - I think I'm a bit of an expert now 

Exactly... don't just pop-in when you've got a question, you can start helping out other's who are having the problems that you've coped with etc, etc.

Perhaps you could make the coffee each morning....

....or the bikkies   

Sorry guys, too busy watching my lovely little fish in their crystal clear water to make coffee/bikkies/bacon sandwich

Water in both tanks now testing nil for everything  chuffed to bits.

My platy still has a red belly though Think it's just her colouring after all.

Sue - have you ever tried taking a pic of a single fish in a tankful of 7 (who is always harrassing another fish so you get 2 every time) in a biorb??? Talk about a challenge!

Anyway, with a bit of help from my son, I managed to get a photo of sorts. You can just make out the red belly if you squint. I'll attach a photo of the biorb and one of Kai so you can see them in a mo (new phone so still downloading them all)

I've noticed another couple of platies are starting to act same way (shadowing other fish until they can get out of the way) but this one is the worst offender.

She doesn't seem aggressive - more of a nuisance to them really...differenet partner every time I look - tart!

The levels are all still nil in both tanks (although Kai's is looking horrible because of the dye in the white spot meds) Hope this is not too good to be true