In my honest opinion those fish are fine in your tank, or at least will be for the next 2-3years. Although there have been reports of 13inch long clown loaches and bala sharks, few bala sharks or clown loaches ever reach this size even if given optimal conditions in the home aquarium...Most clown loaches and bala sharks only grow to about 10inches long, and this often takes quite a few years for them to reach this size. Clown loaches grow very slowly, about 1inch every 4months maximum on average, i'm not sure about the growth rates of bala sharks though.
To be honest, i wouldn't rehome the clown loaches or bala sharks, their chances of getting anything better at a lfs and being bought by another customer is unlikely. And either way, you should have a couple of years to appreiciate them at the least and think about getting a larger tank for them in the distant future, a 6x2x2ft tank would be ideal for them in the future (and to be honest, such a tank isn't much larger than a rio 400 anyway)

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The pictus catfish (although i'm no expert on them) and the golden gourami have more than enough space in the tank anyway. Do you know the gender of the gourami you have? The dorsal fin on male golden gourami's is longer and more pointed than that of female ones.
Right now i would advise keeping the fish you have and concentrate on creating an ideal habitat for your fish to live in to help get the most out of the tank and the space it has to offer

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I would advise creating a planted area at one end of the tank for the gourami, with plants which grow right from the bottom all the way to the top of the water level in the tank, perhaps with a couple of floating plants too if you can get hold of them- this planting is important for gourami's, as in the wild they spend much of their time in densely planted area's.
The rest of the tank should be kept relatively clear, it should have a couple of caves for the pictus catfish and clown loaches to retreat into at the bottom of the tank when they feel like it. A fine soft sand substrate is ideal for such fish, but a fine rounded gravel substrate is acceptable, soft fine substrate is important for such bottom dwelling and feeding fish as it helps keep their barbels/whiskers healthy, as large rough gravel can damage such sensitive organs on such fish.
The rest of the middle to top of the tank should be kept clear to provide a decent amount of swimming space for the bala sharks

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I would say you have plenty of room for more fish depending on what types of fish you get. In a way, you are lucky you were able to rehome your sailfin pleco- i cannot get any medium or large sized plecos for my tanks since my common and sailfin plecos will not tolerate them, i can only get small plecos for my tanks. You now have a lot of options open to you if you are still interested in plecos, since there are a lot of very attractive plecos which grow to 12inches or less which are good for your size tank, like the beautiful Mango/Magnum pleco;
http
/www.planetcatfish.com/catelog/speci...?species_id=191

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I would advise getting another filter for your tank though. The filters that come with juwel aquariums are good but tend to be pretty weak since juwel aquariums are primarily aimed at people that want densely planted tanks with low stocking/little bioload pressure stocking. In the past, i have always added more filtration with juwel tanks, usually placing a second filter at the opposite end of the tank works very well

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