Tail heavy

[layshaft]

) Very newbie to this game, Only wanted a goldfish for my son's birthday however shopkeeper told my that tropical fish were easier to keep. Nemo's got a lot to answer too. However I.ve done alot of reading and research and enjoying MY new hobby.
The problem is I,ve got a pair that the shopkeeper said were YELLOW TAILED CONGA, cant find this name anywhere on the net or in books. 1 x is GREY in colour with RED spots, it has a bright YELLOW marking on the top and bottom of its finn's with a RED line below the marking. Its partner (presume its female) is a plain PINK,y colour.
The promlem is the colourful one (male?) started to sink by its tail, its front finn's are flapping like mad but it cant float level. It has to rest its tail on the floor or on the plants in the tank. It appears to be distrested and is not feeding.
This started after I carried out a water change yesterday.
Any ideas anyone

 

[appleblossom]

Hi Layshaft and welcome to the forum Everyone here is very friendly and they know their stuff!!!

I'm afraid I dont know what your fish might be or what the problem with him is but if you could tell us some more information about your tank then someone will almost certainly be able to help you.

Do you have any easy-test kits or test strips for your aquarium? If so, what do the readings show?
How big is your tank?, How long has it been set up? Is it cycled? How long have the fish been in the tank? Was the water you used in the water change dechlorinated? Have you got any other fish in the tank? Any bogwood, rocks or shell based gravel that could be affecting the water?

The more information we have the easier it will be to help.

 

[layshaft]

Thanks Nutmeg,
I'll try to add picture of the fish in question. Tanks been up and running 3 months now it has 1 x bog wood, 2 x rocks 6 x varius living plants. water tested at local garden centre before water change and was ok. We have 10 x neons 10 x harlequins 6 x rummy nose 2 x spotted hypostomus and 2 x what ever they are.
Its a 70lts juwel tank, we snails I can't get rid of that are eating my plants.
Any help would be appreciated as I dont want the little guy to suffer.