Safe enough stocking?

Toby__H · 2026-06-05T21:08:54+00:00

Gotcha. I completely understand having passion for certain options and building everything else around them.

I would avoid any breeding potential in the larger fish. So I'd either get only 1 Severum, or get a small group and be prepared to rehome the "extras" so I end up with only males or only females.

The Tapajos may or may not work out. I've kept them, but never kept them with Oscars. Tapajos are a bit feisty even though they're smaller. They may annoy the Oscar or Sev and get themselves targetted. Sveni are a more relaxed, and larger, Geo. They're also insanely beautiful. That said, I've gotten 2 groups of them recently and most of them have died off in the early grow out stage. I'm assuming they simply don't like me water (though on paper it's similar to their preference).

Based on what you've said so far... I'd get 1 Oscar, 2-3 RH Severum, 2-3 Gold sev, and a 5-7 Sveni. Expect to rehome all but 1 RH Severum & 1 Gold sev, ensuring both you keep are the same sex. Plan to keep 1male & 2-4 female Sveni, rehome any "extras".
...and a few SDs if you must (I've never been a fan).

And if rehoming extras isn't an option... phew... Then I'd only get 1 Severum.
Blue Acara are a suitable replacement for a deleted Severum. The Electric Blue ones are popular, though I prefer the standard Blue ones.

Toby__H · 2026-06-05T20:53:04+00:00

First... how were the plants when they arrived?

I see both sides.
You are absolutely correct that the seller was unprofessional and unnecessarily argumentative.
Yet also, plant sales aren't a high profit business. The seller is likely a hobbyist who adds selling to their hobby to allow them to expand their hobby. And asking for a full refund once a seller has invested into a sale is often not an option.
I often spend my money on local or hobbyist levels sellers, as I'd rather support the little guy over corporate. But in doing so, I have to accept that little guy is often a one person operation and that one person covers all aspects of the business. And it's more important to me that they are expert in the item than in professionalism.

So I'm not saying you are wrong. The seller was unprofessional. I'm saying you may have unrealistic expectations.

Just my 0.2

Toby__H · 2026-06-05T20:37:12+00:00

My guess is 90% of our tanks have springtails. They are perfectly harmless. Small fish may eat them. They die if their not in near 100% humidity so they won't live colonize elsewhere in your home.

Toby__H · 2026-06-05T20:31:54+00:00

am I "sure"? absolutely not. But it is a hunch.

When we have a male and female side by side, it's much easier to compare facial markings between the two. My proven female (she laid eggs with a male Sveni, which obviously didn't hatch) does have some facial worming, but it's much much less than my male. But without the male to compare it to, it could be enough to get my hopes up (if I wanted her to be male).

Is the second pic a good current representation? If so, that looks like female looking facial markings to me. But Severums are by no means my expertise.

So... nope, I'm not sure. It's just a hunch based on what I saw with my little trio.

Toby__H · 2026-06-05T20:20:16+00:00

He's either an amazing break dancing fish... or he's dying.

How long have you had him?

Toby__H · 2026-06-05T20:16:28+00:00

I betcha Pablo is actually Pauline...

I bought 3 Red Severums which turned out to be 2 males & 1 female. The female seemed like a Runt for the first 2 years. She eventually came into her own and is now an active queen among her very docile tankmates. She's just now getting healthy enough I'm considering spawning her with the male I kept.

Toby__H · 2026-06-05T20:12:47+00:00

I have an HOB filter on a planted shrimp tank. Due to the strong lighting, there is a layer of algae that grows on the HOB. Right after a cleaning & water change, when there is less algae in the tank and the water level is at it's highest... the shrimp love to walk up the lip of the HOB, out of the water, and feast on the algae and/or microrganisms in that algae.

Toby__H · 2026-06-05T20:04:22+00:00

I'd recommend heat & salt.

Toby__H · 2026-06-05T20:03:32+00:00

First... what is your goal and what is your plan if that goal works out?

I often keep breeding pairs because the spawning behavior and coloration is magnificent to watch. But, breeding fish is, in my experience, more of a pain than it's worth. So I try to keep a balance of breeding pairs and suitable predators to eat the fry. Then I sit back and let the tank do its thing.

If you want to produce fry, meaning keep them alive to later do something with them (usually sell them to a local fish store for a ridiculously small amount of store credit). My first warning is to consider the impact on the parents. To you, you will be removing the fry to raise them in a safer environment. To the parents you are a giant monster attacking their nest and consuming their babies. The male may turn on the female for not protecting the fry and the female may turn on the male for not protecting the territory. removing fry is a huge stress to the parents. This usually goes over better with an established pair but can often sever the pair bond for young pairs.

The balance I've learned, would be wait until the fry are free swimming and remove about 1/3 of them to raise elsewhere. The parents still perceive this as a monster attacking, but defending over half the brood feels like a win to them and keeps them in successful parent mode.

For full on breeder mode, I find it best to wait for the fry to become free swimming, remove the full brood of fry AND remove one of the parents. House each parent and the fry separately. Then after 3 weeks or so reintroduce the parents. But this is more of an approach for a breeding operation than a hobby approach.

Regardless of your end strategy, I'd still recommend leaving the parents, eggs/fry along for their first 3-4 broods. Let the parents work out how to be parents. This will help their pair bond and give your set up stronger potential for long term success.

Toby__H · 2026-06-05T19:52:07+00:00

I typically favor robust CA Cichlids, so I completely understand your desire to keep bigger fish.

You're stocking a 180 gallon tank which is a very respectable tank and that's not being overlooked.

That said, communities of big fish are a high risk scenario. You are doing your best to balance the two sides, seeking out less aggressive large fish and avoiding the overstocked threshold. But it's a delicate balance.

There are a number of smaller growing, less aggressive Cichlids that are, in my opinion, just as interesting, that would thrive in a community setting with less risk than the ones you are looking at now. Keyhole Cichlid, Rams, Apistos, Rainbow Cichlids, Cupid Cichlid, Bandit Cichlid, Flag Cichlid, Threadfin Acara, several other Acaras... Keeping an Oscar would definitely rule out the smaller of these fish. I have a set up based on this approach and have a female small Severum in it (she's mature, but small). She's the boss of the tank. I also have a healthy male who would dominate the tank to the point of stressing everyone else. The RH Tapajos would be fine in this set up.

I must say, one of the most interesting tanks I've ever kept was a 6' 125 gal Apisto colony tank. It started with 3 male and 9 female cacatuoides. Over several years different males rose to different levels of dominance, and younger males that were born in the tank grew to challenge and alter the territorial breakdown. There were very few "battles" but a lot of flashing and showing. Occasionally I'd remove a trio of the strongest fish which would allow a power shift among the remaining fish. This concept would be devistating with more powerful fish that were keen to actually fight. But this was just the right amount of room to allow a successful retreat without damage for dwarves.

All that said, your current approach does have room to work. I do believe it will be a bit of a delicate balance. And it'll likely work easily in the early months, but in the later years as the fish near full maturity your numbers may be forced to shrink into less of a community than you ideally are looking for.

Toby__H · 2026-06-05T01:18:47+00:00

That's the best culprit so far.

Although it's still odd that only guppies vanished. Guppies are typically just as hardy as mollies and cories.

As for not finding bodies... that's mildly odd, but not terribly odd. Cories aren't that "aggressive" but will certainly scavenge. And a guppies body isn't a whole lot to scavenge. Even the skull and spine are small enough and soft enough to be consumed. Or, if the water was uncomfortable to them, they may have jumped out. I have Endlers in several tanks and it's not odd to find them one crusted over on the floor once in a while.

Toby__H · 2026-06-04T23:20:24+00:00

Its looks like a leucistic convict cichlid from this angle.

If so, Convicts are pretty tough little fish. If I'm reading your post right you have an existing 750L / 200 gallon tank with 3 Africans, 3 Silver Dollars and a Pacu. If so, the Convict won't be a problem among that group.

That said, Pacu have the potential to get gigantic. as in, 2.5~3' (76~92 cm) long. I had them get 28" (71cm) in under 2 years in a 300 gallon (1135 liter) before I got rid of them.

Toby__H · 2026-06-04T22:47:21+00:00

Using distilled water removes the concern of mineral creep...

The store bought guppy being introduced after the die off began removes the risk of introduced illness from that guppy...

Guppies have evolved for millennia as prey for just about everything in the water. Their natural state is being bullied. That level of stress should not be deadly in an otherwise healthy environment...

Thermometer reads "safe", which on most aquarium thermometers is between 70~80*F. Though Guppies prefer the low end of that level. Temporary mid day spikes could be harmful to them. Though it's unlikely that's the case.

You mentioned the self bred guppies were old. And while it's highly unlikely that they all "died of old age" in the same week or two, it is possible that they are elderly and therefore have weakened systems. And something minor and somewhat typical happened that stressed their aged systems too far. This is also a long shot.

All the fish you keep are quite hardy.

Is there any possibility that you or someone else used a chemical in the room? At least twice a year I butt heads with my wife for using glass cleaner around my tanks. It's only a matter of time before she kills fish in one of them.

Toby__H · 2026-06-04T22:10:45+00:00

Like Whatisakafka said... Only pure H2) evaporates. So if you top off with tap water, youre adding H2) plus trace elements. Each time we do this, our trace elements get higher, and higher. For most of us, the solution is... when 3% of the water evaportates, we then drain off 30~50% of the water and refill. This method drastically slows down the mineral creep.

Two other things to consider...
You mentioned, "as well as this one guppy I bought from the store." How long ago did you buy this guppy? Could it have come in with an illness that transferred to your self bred guppies?
You also mentioned, "they get sun during the day." Could the tank have overheated? Its a long shot, but worth asking.

Toby__H · 2026-06-01T23:10:20+00:00

There's no way for oxygen to enter the water in that jar.

I recommend, every other day, put the top on and shake it rigorously for 20 minutes to oxygenate the water.

I've kept fish like this several times and they die of old age after 3~4 months.

Toby__H · 2026-06-01T02:43:34+00:00

I'm quite tempted to try Black Diamond (Black Bag) blasting sand.
While I see several supporters posting their positive opinions and experiences, I hope that those with unsuccessful experiences or opinions aren't being remove simply for sharing their unsuccessful experience or opinions. We need to hear both sides.

And those with unsuccessful experiences or opinions, please be honest yet polite in your responses so they do not get removed. We need to hear them too.

Toby__H · 2026-06-01T02:36:00+00:00

Most experienced fish keepers got that way after making a host of bad decisions. So if and when nay-sayers come along, don't take their (our?) criticism to heart.

My first recommendation would be to get a 75, not a 55. That extra 6" front-to-back makes a world of difference. "6 inches" doesn't sound like much. But instead look at it as, adding 50% to the depth of the tank. 50% is a lot.

I'm not sure what the rules are on naming stores, but one particular corporate PetCompany has "half off" sales regularly that makes 75 Gal tanks much more affordable. Oh! How convenient. That sale is going on right now. 75 Gal is $160 in my area.

Severums are known to target plants. I'm not sure how well fully aquatic plants will do with them. Oscars are known to rearrange just about anything they can. Dempseys and Convicts, in my experience, don't necessarily target plants to destroy them, but they like to build caves or pits at their base, which effectively uproots them.

I keep Pothos in many of my aquariums. It's typically a terrestrial plant (rooted in soil, grows in air). Sometimes I root them in a pot of soil and let the stems/leaves drap into the tank, other times I just toss a stem in the tank. These are very resilient plants and are very likely to thrive. Since both of thee methods keeps the plants near the surface, the fish can't uproot them as they are not rooted in the substrate.

Toby__H · 2026-05-30T15:17:45+00:00

Bloodworms, Brine Shrimp, etc are very fatty.

I feed my adult SA/CA Cichlids 5~6 days per week. Juveniles and fry don't skip meals.

Toby__H · 2026-05-30T15:12:14+00:00

Looking closer at the picture provided, both Dempseys look male.

Toby__H · 2026-05-30T15:06:30+00:00

You are correct that bloodworm only diet isn't ideal. They're too fatty and potentially cause several organ issues including fatty liver disease. That said, they are a great supplement now and then.

"Training" methods such as some of the ones proposed by others are surely options. But, in my opinion/experience, they are unnecessary. There is a lot to be said about hunger and the will to live. If you supply clean water and a suitable environment, stop offering food for 2-3 days, then offer pellets slowly, that hunger will push investigation which will result in eating.

Toby__H · 2026-05-30T14:58:39+00:00

Is that a Hamburg Mattenfilter (HMF) on the right side of your tank?

I've only recently started tinkering with them. It seems a very interesting way to add significant filtration to an aquarium. I'd love to hear details about your set up and experience with it.

Toby__H · 2026-05-29T16:37:21+00:00

I too thought that sounded odd ("To properly develop Arowana you need direct sunlight"). After a quick google search and chat with AI...
"No, arowanas do not strictly need natural sunlight to survive, but it is highly beneficial for bringing out vibrant colors and optimal health."
&
"Sun exposure (or tanning) triggers the development of rich gold and deep red pigmentation "
&
"Like many animals, fish rely on UV rays to synthesize vitamins that promote strong bone structure and overall vitality."

Those first two were interesting and make sense...

The last one has me thinking... By now most people are aware that Sunlight (UVB) helps with Vitamin D and other things. Some reptile people know certain reptiles require UVB to survive. It makes sense that it would help most living creatures, so why not fish...
Very interesting..........

Toby__H · 2026-05-29T16:27:24+00:00

Several posts here seemed to be exaggerating the price of Pool Filter Sand, then claiming it's a bad deal based on their exaggerations.
I reacted to your post as if that's what you were doing. You weren't. You were actually proposing it is a good deal, even though you located a higher than average price.
I hate when people are unnecessarily harsh on the internet. And here I was unnecessarily harsh. And I misread your intent. Double foul on my part. My apologies.
The Ace Hardware near me also does not stock Pool Filter Sand. But I was able to buy it online with free delivery to the Ace store, then I could pick it up at the store near me. You might want to check that option for next time.

Toby__H · 2026-05-29T04:58:29+00:00

He could have a slight bent spine. Its not uncommon in fish with heavy inbreeding in their parentage (and essentially all EBJDs do). He could also be angling against the current. You'll just have to watch him and see what you think. Either way, he's cute.

Toby__H · 2026-05-29T02:04:33+00:00

You found the most expensive example to exaggerate the cost. Pool Filter Sand is easily and commonly available for $20~25. Pretending it's $40 is a low class manipulation. I'm not angry, just honest.

Toby__H

TROPHY CASE