Today at the local petshop they seemed to have upgraded as they had everything from lobsters to toads.

They seemed to know their stuff and have little notices everywhere saying what you needed for each type of fish, all the usual correct stuff about 20 galleons per commet etc.

Anyway they had these cute small 'upside down catfish' and the sign said they could be kept safely with medium sized goldys. First off i'm very curious if this is true, they were adorable.

Secondly they had the tiniest cutest toads which it said although they eat very small fish they could be kept with larger goldys, again i wouldnt mind one.

Lastly they had small lobsters. It said they could be kept with large goldfish however i would never in a million years put one with my goldys...they looked wild lol

Just curious.

If that's true, I totally want one!

srry, I have no advice..................

UDCs are tropical fish...I actually own 3. I would not recomend them for gf tanks. They enjoy heat so much that mine hide behind the heater

well, i wouldnt keep them together. only because once your goldfish start to get big, they may eat them.

Someone once wrote about extracting a catfish from the mouth of a goldfish. Sounded absolutely horendous. At my lfs I saw a tiny toad with each of its hind legs in (two different ones) a salamander's mouth. (I did get one of the workers to free the toad.) I would be afraid of something similar like that happening with a goldfish.

I remember that post about the catfish being swallowed too. All kinds of things can happen it would seem. I am no expert but toads and lobsters would seem a big no and UDCF well, some people have them with goldies but usually in a large tank with lots of hideyholes. Better wait for more info on this from people who keep them.

I've extracted Cory Catfish from a Goldie's mouth twice,and it was not a very nice experience,believe me. In general, The UDC get around 3-4 inches big and are considered a dwarf catfish.IMO,I consider the Upside down Catfish a peaceful loving,laid back kind of fish .They can deal with temps in the lower 70's,but they tend to do better with moderately soft and slightly acidic to neutral water. A well-planted tank is ideal, preferably using broad-leafed plants, as they like to browse the undersides of leaves. Driftwood, rock arches, and caves that provide places to hide, are recommended. It is quite normal for this fish to hang out on the underside of rocks, leaves,etc. As our goldies grow big, need extra powerful filtration,normally are in a plantless tank as they tend to eat them all,and really need their ph on the higher side,I don't feel that they are a good choice to go with goldfish.
I'm not sure,but chances are that you saw either African clawed frogs or African Dwarf frogs in the tank if the tank was fully aquatic.
African dwarf frogs barely get 2 inches or so big.They can't handle alot of powerful filtration,and they need to go to the top on occasion to take a breath before they can stay submerged for a good while. I can't tell you how many people have told me that their frog got grabbed by their goldfish when the frog came shooting up for some air. Unfortunately,these frogs stay "Bite Size" for goldies,and although it may work for a bit,at some point there will be an accident,so it's not a good idea at all to house them with goldies.The frogs finding food would be another major factor on that. Other things like PH,temps,big water changes etc. all affect these little frogs and they tend to die rather easily from them.
I have known a few people who have kept Clawed frogs with Goldfish for a while,but in the end they've always ended up seperating them.A clawed frog's body will get to be the size of an adult closed fist,and that's not counting it's length for arms and legs. They are Predator's and will go after and eat anything that they can fit into their mouth.I learned that the hard way when I had a clawed frog that was still pretty tiny.I let him share a tank with a betta,and things were fine for a while until one day I walked in and saw him swallowing the last of my Beautiful Red Male Crowntail Betta,who was huge in comparison to this frog. I will never get that awful picture to go away as it really shocked me alot. They have voracious appetites and will be in constant competition with your goldfish for food,and your goldfish could possibly end up being their dinner.
Ther are a few types of Lobsters that you see in the Pet store.Yes,they say that you can keep them with bigger goldfish,but the trick is to figure out how big.These too can also be considered Predator's as they have been known to attack fish as they are sleeping on the bottom at night.Lobsters are really best kept in a species only tank.
Sorry,as I know I haven't probably given any answers that you were hoping to hear,but I can only give you what I've known or read,or experienced,and this is only my opinion.

I would not reccomend ADFs... I kept two with my 5" ryukin and things were fine, but she seemed to get very curious and see them as food when they darted up to the top. She'd 'nudge' them sometimes to get a smell, but for the most part she left them alone... I can bet that if she was big enough to swallow one and one swam past her she wouldn't hesitate to gulp it down without thinking twice. The frogs spent most of there time hiding and would only come out for air. These little guys don't have the best eyesight either and are bottom scavengers... they can't compete with a hungry goldy. I have since moved my two frogs (along with a new female) into a 6gal. eclipse tank by themselves and they seem to love it in there. They are much more active and spend most of the time out of there hiding holes.

I don't know on the upside down catfish or the frogs, but I have known several people with several different types of lobster and crawfish.

Inevitably, the salesperson tells them that it can work in a community tank, and inevitably, within a few days of being put in the tank, the arthropod starts to methodically dismember and eat every fish within in...even ones much larger than itself.

Maybe not true for this one, but most of the accounts I've heard from my various relatives have been about the blue lobsters...

wow i forgot i started this topic ages ago and reading the responses now i'm extremely glad i didn't buy any, they were the dwarf frogs i think.
Some of the responses, especially Devs were fascinating and i learnt quite a bit just now.

ta =]