Advice on stocking a 6ft oscar tank

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Kish

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Original poster
Oct 12, 2019
12
1
3
Queensland, Australia
Hi All,

I finally have the space for a big tank and am going to have one custom made in the coming weeks...very exciting stuff! Still planning out the design for the equipment, sump and cabinetry, but thought I'd get some advice now on stocking it to make sure I'm heading in the right direction.

It'll be 6ft x 2.5ft x 2.5ft. Will have a large sump - still not sure how large, as it depends on the cabinetry - but definitely going to have good turnover (would be aiming for 8-10 x per hour).

I want to keep it simple to highlight a few of my favourites. Currently thinking about:
2 x oscar (tiger)
12 x spotted silver dollar (metynnis lippincottianus)
8 x clown loach
1 x common pleco

The plan would be to get the silver dollars, loaches and pleco settled in and grown to a good size first. When the loaches are about 4", I'd add two small oscars.
In terms of hardscape, I'll have large, rounded grey rock with lots of interesting driftwood to give the pleco and loaches plenty of hiding space. Natural coloured sand substrate.
Will have to see how many plants I can get to survive in there with the silver dollars... Will try some java fern and moss grafted to the wood, water sprite and floating water lettuce or frogbit to start with.

I know that clown loaches aren't exactly what you'd expect with oscars but I love them and I'm hoping it can be done. The closest I've personally done is added juvenile clown loaches in with a breeding pair of blue acaras - they didn't bother each other at all once the initial curiosity wore off. The general consensus on google seems to be that, assuming they grow up together, they'll be ok...but I'd be interested in views as to whether it would work or not.

What do people think of the mix? Will clown loaches be ok? Have I got the numbers right?

Looking forward to hearing some views! Thanks in advance!
 

fishorama

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Jun 28, 2006
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SF Bay area, CA
It seems a bit heavy on stocking to me. All except the silver $$ get 8-10 inches or more, depending on the pleco, some get 18+". I understand you'll start with small fish but you need to allow for adult sizes. Maybe fewer $$, say 6? I haven't kept them but they may eat plants, many do. I fed clown loaches & plecos veggies like zucchini & romaine a few times/week that might help with $$ too.

Oscars can grow fairly fast as can plecos, both eat & poo a lot!! Even with a sump I'd think you need to poo vacuum a couple times a week & do a major water change at least once/week. That might be a PITA in a large tank unless you plan on a system to help with that.

All that said, that's a bigger tank than I've ever had :) I wish you good luck! & we'd love pics
 

the loach

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Aug 6, 2018
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This tank is about 260 gal... it would be way overstocked if you did that.
2 oscars and a pleco will be fine... with 6 silver $ max, or a school of 4-5" less deep bodied schooling fish.
When you get a pleco don't buy a small one but please adopt/rescue a big one. There are many waiting in small tanks, as well as oscars.

Clown loaches get too big... also most of them loose their markings when they mature. You would need like 600 to 750 gal (depending on the footprint) to house 8 comfortably.
 
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Kish

AC Members
Original poster
Oct 12, 2019
12
1
3
Queensland, Australia
It seems a bit heavy on stocking to me. All except the silver $$ get 8-10 inches or more, depending on the pleco, some get 18+". I understand you'll start with small fish but you need to allow for adult sizes. Maybe fewer $$, say 6? I haven't kept them but they may eat plants, many do. I fed clown loaches & plecos veggies like zucchini & romaine a few times/week that might help with $$ too.

Oscars can grow fairly fast as can plecos, both eat & poo a lot!! Even with a sump I'd think you need to poo vacuum a couple times a week & do a major water change at least once/week. That might be a PITA in a large tank unless you plan on a system to help with that.

All that said, that's a bigger tank than I've ever had :) I wish you good luck! & we'd love pics

This tank is about 260 gal... it would be way overstocked if you did that.
2 oscars and a pleco will be fine... with 6 silver $ max, or a school of 4-5" less deep bodied schooling fish.
When you get a pleco don't buy a small one but please adopt/rescue a big one. There are many waiting in small tanks, as well as oscars.

Clown loaches get too big... also most of them loose their markings when they mature. You would need like 600 to 750 gal (depending on the footprint) to house 8 comfortably.

Thank you both for your responses - I really appreciate the advice.

I'll definitely reduce the numbers of the spotted silver dollars and clown loaches - go with fewer of each... Maybe go back to the drawing board on the loaches entirely.... And will definitely try to rescue where I can - I agree that's really important. There are far too many large species struggling in small tanks.

With the exception of the oscars, I've kept all those fish before...just not in the same tank or at the same time. I had a breeding pair of blue acaras at one point, which I adored, so oscars seemed like the next step for this tank.

My clown loaches got to 6-7" but then I had to move house and couldn't hold onto them. Ended up giving them to an aquarium nearby to put in a monster display tank - they had some mature ones there and mine were welcomed into the family. :) I've missed them ever since though.

One thing I noticed was that my spotted silver $ stayed smaller than regular silver $ that I've seen elsewhere... Is that normal?
The only way I could make plants work was to give them lots of veg to eat and use moss and java fern (which they teared a little bit but wouldn't eat). I would then rotate plants between tanks so that they could recover... So, this time, I'll be using both regular and narrow leaf java fern (grafted to removable sized driftwood/rock) and will keep some in my refugium so I can rotate them through.

Right now, I'm looking at being able to fit a 4 or 5' sump underneath. I'll go as large as will fit in the cabinetry.

Still, I agree with you, fishorama, this is going to be a high maintenance tank. It's why I've waited so long to do it - I'm semi-retired now and work from home...finally feel like I can put the effort in. My plan is to set up a 400L water tank outside to hold used water, which I'll then use on my garden over the following week... Obviously water can be removed easily from the sump intake but I also want to use a hose with a long vacuum attachment inside the tank. If anyone has any ideas on making the design as easy as possible to work with, feel free to let me know!
 

the loach

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Aug 6, 2018
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One thing I noticed was that my spotted silver $ stayed smaller than regular silver $ that I've seen elsewhere... Is that normal?
Fish will be stunted when not given enough space...

There are other loaches and catfish in the 4 to 7" range that are more suited to your tank. Of all fish, clown loaches are among the most sociable you can't really cut in their numbers.

We have a member that has silver $'s in a planted tank, you might want to take a look at his posts:

 

fishorama

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Jun 28, 2006
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From my quick google, it seems spotted $$ are smaller than some others, only to ~5 inches.

I too bred acaras at 1 time & loved them :). I kept clown loaches until I had to move & had to do the same as you, lfs display (sniff).

Is your heart set on Oscars? As TL said maybe smaller cichlids, smaller loaches & a different pleco species. Severums or geos? We kept acaras with firemouths at 1 time, just saying...both bred but (thank goodness) not more than a few fry survived to grow beyond food size. To me that every month cichlid breeding thing gets old after a few months.

I've kept several loach species, I'd say histrionica are a close second to clowns. Very day active, people & plant friendly IME, not quite so pretty but nice. & since they only get to 5 inches you could have a bunch for more loachy fun! (I have yet to keep kubotai, slightly smaller, they may be next! Maybe both species? OK loach enabling you, lol). But I'm concerned they may be Oscar food...with possible a choking hazard with the eye spines or smaller plecos with pectoral spines...It may depend on the Oscars' tolerance especially if you get a pair that want to breed eventually. Think long term...& lots of loaches if you can...
 

Kish

AC Members
Original poster
Oct 12, 2019
12
1
3
Queensland, Australia
Fish will be stunted when not given enough space...
I doubt it was that. I got them mature from a school of 16 in an 8' tank. They're a different fish to standard silver $ - and the size difference is quite noticeable. More noticeable than I originally expected it to be, but I haven't seem them side by side in the same tank irl.

We have a member that has silver $'s in a planted tank, you might want to take a look at his posts:
Thanks for that! Very cool.

I'm wondering if I get mine younger this time and start them out in a tank with established plants and a good feeding schedule, that might make the difference. Mine were older when I first got them and I think the environment they're raised in can have an impact. I did notice that he's chosen similar plants to what I have on my list, so that's good.

He states he has 3 species and some look to be spotted... I think they're the noticeably smaller ones in the first picture. So that gives me an idea of relative size - definitely much smaller so I can probably keep a couple more.

I too bred acaras at 1 time & loved them :). I kept clown loaches until I had to move & had to do the same as you, lfs display (sniff).

Is your heart set on Oscars? As TL said maybe smaller cichlids, smaller loaches & a different pleco species. Severums or geos? We kept acaras with firemouths at 1 time, just saying...both bred but (thank goodness) not more than a few fry survived to grow beyond food size. To me that every month cichlid breeding thing gets old after a few months.
How funny!

The breeding is a PITA, isn't it? I was just writing on a different forum about how mine would breed continuously...and I've actually talked myself out of having a pair... There's more digging and aggression and, while the breeding pair seemed happy enough, I always feel guilty leaving fry in there to become food for their own parents. I started separating them out but then ended up with hundreds of blue acaras that I had to get rid of... Don't want to deal with that again tbh.

I don't really want to do smaller cichlids again and I like the idea of simplicity for this tank. I don't want a lot of fish; I'd rather have fewer larger ones. My other tank will be busier and I want this one to have a different aesthetic.

I went back to the drawing board last night (I'm clearly in the early stages of planning, hey!). I'm now thinking I could go with just 1 oscar as a focal point, along with 8 spotted silver $ (given they're quite a bit smaller than the standard ones).

As for some bottom dwellers, I don't love too many other loaches and I'm concerned that histrionica and kubotai are just that little bit too small and a choking risk for an O at full size. He/she's going to grow fast in this tank, after all. While, I still would love to have 5 or 6 clown loaches running around - and I think I have the space and filtration for them at least for many years - if it won't work, I've got another idea...
I was thinking some fast moving catfish... I had synodontis multipunctatus (cuckoos) breeding with some african cichlids in the past and they were quite nice to have around - certainly brave and speedy to get in between a couple of breeding malawi cichlids! So, what about pictus catfish this time around? I haven't kept them before but I think I'll have enough cover/driftwood for them to hide, they're significantly smaller than clown loaches and very quick. I've seen them before with full sized oscars and other forums seem to be positive... Views on pictus catfish over clown loaches welcome.

As for a pleco, maybe omit it entirely or go for a rhino pleco, since I think they stay several inches smaller than the common and sailfin plecos. Will look into that further and find some medium-sized species if I can or just leave it out.

I haven't moved far but I think omitting an O opens things up a little.

Right now I'm looking at a tank size of 72" x 30" x 30" with a 60" x 24" x 18"-24" sump underneath and a lot of turnover. I might even be able to get another few inches on my tank length depending on the plumbing. Fingers crossed. I want it to be a long term tank and not overstocked when the fish hit full size but, on the other hand, that's a lot of volume and I want to use it effectively.
 
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fishorama

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Jun 28, 2006
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SF Bay area, CA
Yeah, trying to find a LFS to take our cichlids juveniles within 40-50 miles...we were persona non grata or at least acaras were non-grata, lol.

Just 1 Oscar, 8 $$, skip the pleco... then I'd get 6-8 clown loaches!! No, not perfect but, sigh, so very very tempting. I'm wondering at what size slower growing clowns would be safe with a fast growing Oscar... In your original post you said you'd get $$ & loaches first & grow them out...before getting the Oscar.

Now, I'm going to say, loach lover that I am, we had trouble keeping young loaches with CA cichlids. Yes, they were skunks & we only had 2 1 inch long 1s with a half grown Jack Dempsey & some other cichlid maybe severum. The loaches were always hungry as young fish are, & skunks are more aggressive than many loaches but... My theory is that the loaches learned that cichlids often spew food from their gills & would check out the "food dispenser" often bugging the cichlids, no actual damage was seen. But that was in the days of under gravel filters & when we tried to catch them they'd go under the plates as soon as they saw a net. It was a total tear down to get them out eventually.

I mention that because I've read of "aggressive" clowns a few times. Again I think it likely it's underfed youngsters looking for food or (horrors!) a single clown. But some of that is keeping fish from different continents together...not always a good option. I'm all about loaches if you couldn't tell :)
 

Kish

AC Members
Original poster
Oct 12, 2019
12
1
3
Queensland, Australia
Agreed - I've seen some weird posts about loach aggression online...but, whenever you read it through, there's usually something off (tank size, sub-optimal numbers, tank mates that would outcompete for food). With the exception of breeding time, mine got along fine when I put them together...but I'll obviously keep an eye on them, as you suggest, to make sure nothing untoward happens. Personality is always a factor.

Yeah, I'm super tempted by this concept. I acknowledge it's not perfect but it's not overly offensive either. I mean, Youtube has some truly offensive examples if you search for oscar with clown loach. Eek. I'm not in that territory. If I do this, I'll have 6 loaches to make for a happy group. And, you know, in 10 years if they get all fat and seem cramped, I can see myself getting an 8' for them... Who needs a bedroom anyway. :)

Yep, I would absolutely get the loaches and silver $ grown to a decent size before adding a juvenile oscar to the mix. I'll try to rescue some larger ones but options are limited where I am now, so I will probably have to start out with juveniles. Honestly, I don't mind if that's the case or if the growing process takes a year - it'll be an awesome tank even without the oscar. Not going to risk any lives being impatient.

I've been googling oscar guides. One says tank mates "over 3-4” with suitable rocks and Caves will be fine", but I'm skeptical... Another one says anything smaller than 5" with a full sized oscar is a gamble... That sounds more like it to me.

I was thinking of targeting 5" before even adding the oscar to be on the safe side... What do you reckon?

Do you recall how yours grew? It was a while ago for me. I remember my clowns starting out small, like under 1.5", and then I think it took less than a year for them to get to the size of my phone (~5") but there was variation - one was bigger and I called one Runty. I can't remember exactly how long it took though. In any case, after that, they seemed to slow down and fill out more. I gather the rule of thumb is 0.5"-2" per year after the initial growth spurt.

So, worst case scenario, by the time the oscar is 1yr old and say 10"-12", the loaches would be a minimum of 5.5". The spotted silver $ should be full sized in that time too - about 5" but not as edible in terms of shape. Then, by the time the oscar hits full size at around 3 yrs, the clowns would be at least 6.5". Safe. I'll put the effort into feeding and water changes, of course, so hopefully they'll be much bigger.

PS: I really appreciate all your advice and thank you for taking the time to brainstorm with me! Your love of loachies is abundantly obvious! :)
 
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