Righto *puts on fish hat* Annoying question time :
How big is the tank exactly?
You need a 3.5 - 4 foot tank for one
pair because they are a large growing species of cyprinid ( carp ) . So at least 40-55 gallons for just two goldfish to be able to swim and grow correctly.
[The avarage size is about 10 inches in fancys like fantails, lionheads ect and up to ( and in many cases over ) 14 inches long in normal bodied goldfish such as comets, shubunkins ect. You know the huge fat ones you see in ponds? THAT is the average size of a goldfish. It isn't giant due to being in a pond, that is how they are meant to look.
They are really really messy buggers. They produce a lot of waste so I hope the filter is large , preferably an external cannsiter seeing as you have 4. I'm very glad you at least bought a filter of some sort which is more than most people bother to do!
I won't ask if you cycled it at all let alone fishless, as from the info given it seems unlikely. Still, if you've had them this long you will have undergone whats known as a "fish- in" cycle. And with such a messy species your bacterial colony will be mature by now anyway.
What sort of sucking fish is it? I really hope you aren't going to say a plec!!! The common ones get as big as and bigger than goldfish in many cases. If it is a plec I seriously suggest you rehome it. A picture would be great so we can know what it is you have. If you don't know what sort of plec or loach you've got you may not be caring for it's needs correctly ( not your fault if no one told you ) Plecs are also tropical fish so if it is one then don't keep it with goldfish.
The reason I ask about tanksize first off is because there may not be enough room in there, and so bickering and ganging up occurs due to overcrowding. Overcrowding is also a contributing factor in stunting growth in goldfish, the biggest factor of all is tanks that are too small and lack of filtration to go with it.
The body type of goldfish is also something to consider. Fancy types with rounded bodies and long droopy fins are poorer swimmers due to the way they have been selectively bred. Their fins and muscles aren't as efficient because of their altered body shapes. So they are slower at getting to food, are a little more prone to things like bloating and swimbladder disease, and find it hard to escape bullies in the tank because they can't get away quick enough.
Normal bodied goldfish are the most natural shape of course, so they are big active fish, and can have a tendency to pick on weaker fish and eat all the grub first.
Is there any way you can re home 3 of the fish( the bullies for example ) and the sucking fish if your tank is significantly less than 5 foot long minimum?
DO NOT KEEP SPLASHY IN A VASE. There is no problem keeping him by himself, they aren't generally a schooling species and are perfectly fine kept alone.
Go out as soon as you can and get the biggest clear plastic storage bin you can make room for. Wilkinsons do big ones for a fiver
http://www.wilkinsonplus.com/invt/0239167
Set that up as a holding tank for Splashy, using dechlorinated water, and an internal cannister filter such as a Fluval 3 . Cut a small hole on the edge of the lid for the wire on the filter to come out, and also drill a few holes in the top of the lid to allow air in so that oxygen can mix with the water. Position the filter outlet pipe ( where the water comes out ) so that it sits half in and half out of the water. The surface of the water must be moving or at least rippling constantly, as that allows better oxygen absorbtion. ,
Seeing as he's more than likely stressed from the bullying, add some fake plants for him to hide in, and a light layer of gravel ( about an inch ) . It won't look amazingly spectacular, but it will keep him away from the bullies, and cut down on his stress which can lead to disease like whitespot.
You will need to do twice weekly 50% water changes on the plastic tub using
dechlorinated water. WITHOUT FAIL. You should be doing the same on your main tank as a matter of course anyway seeing as you have so many messy fish in it.
No offence, but in future you should advise your in laws not to get fish on a whim , even the most commonly seen "easy" species like goldfish, all have the same basic needs, and really do require a lot of research and planning before you even add a drop of water to a tank. You are basically creating an ecosystem in a glass box and it's entirely up to you to keep it in balance to keep the fish healthy.
The best thing you can do is try to rehome most of the fish and keep just 1-2 ( say, Splashy and one of the most peaceful of the other fish ) . If your tank is less than 3.5- 4 foot long, then rehome them all, it will be the kindest thing.
If you do rehome them, you can simply add a heater to your main tank and keep some basic tropical fish. They are no harder to keep than goldfish I can promise you. In fact goldfish are more hassle in terms of basic living space and the amount of waste they produce.
If you need any help I'll be happy to help you.
a few days after the new inmates arrived...
