Big scavengers, little fish, in community tank?

[OldTownSta]

In a 125 gal. small & medium fish (from neons & guppies through mollies &
kribs) freshwater tank...

1) At what size, if any, does a Pl*co become a concern with regards to eating
smaller fishes? When I got him, that suckermouth just looked so herbivorous
and non-threatening, but as he approaches 8", I wonder about my neons....

2) Ditto black ghost knife? Small mouth, but big fish. 5" too big? 6"? 7"?

3) Ditto Raphael cat. This guy is only maybe 4" or 5", and hardly seems to
move, much less eat, but dang he's got a big ol' mouth...

Also, in a fry tank, with a couple itty bitty cories serving as nannies, what
species (and size) would be relatively safe as an algae eaters to police the
side glass?

Thanks in advance for any suggestions! -- Jim

[McEve]

"OldTownSta" > wrote in message
...
> In a 125 gal. small & medium fish (from neons & guppies through mollies &
> kribs) freshwater tank...
>
> 1) At what size, if any, does a Pl*co become a concern with regards to
eating
> smaller fishes? When I got him, that suckermouth just looked so
herbivorous
> and non-threatening, but as he approaches 8", I wonder about my neons....

I have catfish up to 8", and they haven't taken any of my tetras. Suppose it
could depend on the type..

>
> 2) Ditto black ghost knife? Small mouth, but big fish. 5" too big? 6"?
7"?
>

Not so small mouth :)
http://www.diskusjonsforum.no/akvariet/attachment.php?attachmentid=170&stc=1
These ones I know take smaller fish and wouldn't venture keeping them with
tetras - generally speaking, I understand Pirhanas are tetras as well, so in
that case the Black Ghost would be the one living dangerously :)

[NetMax]

"OldTownSta" > wrote in message
...
> In a 125 gal. small & medium fish (from neons & guppies through mollies
&
> kribs) freshwater tank...
>
> 1) At what size, if any, does a Pl*co become a concern with regards to
eating
> smaller fishes? When I got him, that suckermouth just looked so
herbivorous
> and non-threatening, but as he approaches 8", I wonder about my
neons....

Really depends on the pleco, but generally speaking, even when they get a
carniverous streak going, they are not really equipped for hunting down
little fish (in regards to mouth apparatus or in bouyancy in a chase). I
t will look really dramatic when he gets to about 18 to 24" long ;~)

> 2) Ditto black ghost knife? Small mouth, but big fish. 5" too big?
6"? 7"?

Now here is a well designed nocturnal hunter, who actually has quite a
large mouth. I feed mine Discus delight and Beefheart. At 5" he would
have no trouble swallowing a Neon. Whether he was inclined would depend
on many variables, including luck. Carnivores raised with prey will
often cease to recognize their tank-mates as prey, however, this balance
is easily upset by adding more or different prey. Add some small Black
neons and the BGK might get curious enough to take them out, and then
your Neons will be on borrowed time. Even adding new Neons can trigger
the reaction. They will react in fear to the BGK, instead of
familiarity, thus making the BGK wonder what the new Neons could be
afraid of. It's not good to get carnivores thinking too much ;~)

> 3) Ditto Raphael cat. This guy is only maybe 4" or 5", and hardly
seems to
> move, much less eat, but dang he's got a big ol' mouth...

In theory I agree. In practice, I too rarely see my Raphael's moving.
I'm concerned that the typical aquarium isn't really a good environment
for these guys. I have no idea if they would be putting your Neons at
risk.

> Also, in a fry tank, with a couple itty bitty cories serving as
nannies, what
> species (and size) would be relatively safe as an algae eaters to
police the
> side glass?

Otos, though in a fry tank, I don't clean the algae, as it's home to
infusoria which is fry food.

NetMax

> Thanks in advance for any suggestions! -- Jim

[OldTownSta]

Thanks McEve & NetMax! The BGK pic was quite an eye-opener! So THAT's where
the half-grown guppies have been going..... -- Jim