Pelcos- Do they out grow tanks?

Hi,

I'm a newbie to the group and picking up my freshwater Aquarium Hobby
after 20 years.

I had fish and two tanks as a youth for about 10 years up to the start
of college.

So I have a few questions I'd like to ask the group over the next few
weeks. I hope I don't overtly display my ignorance. It seems I've
forgotten a few things over the years and their are quite a few outright
experts here. Anyway:

Question #1:

I restarted with a 20 community tank. Lots of plants (Amazon Swords and
floating Hornwort), a couple homemade caves, some small apple snails
which came in with the plants , a Betta couple, a rainbow shark, a
Common Pleco, and (finally) 5 swordtails to fill out the tank.

The tank is just over 4 months old and seems to be doing very well.
Fish are getting along with each other and the water is crystal clear.

I'm worried about my Pleco though. He doing really well, but perhaps
too well. I got him for very cheap and he was described as small but
was already an inch long. I'm guessing he is 4 inches now and has a
large girth. Will he outgrow the tank? He is quite nocturnal, and
somehow manages to stuff himself inside my homemade rock caves (with
tail often sticking out) during the day. I was under the impression
that most fish will only grow so big in accordance with the size of
their environment.

Will he outgrow my Tank? I only have one and don't want to give him
away. He is a beautiful monster! Am I overcrowding my small Tank?

Cheers,

Trev

--
Trevor Stenson

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