Undergravel filtration and Cory group fish

[TwoTankAmin]

I had a pre-filter sponge on my powerhead. So, during weekly maint. I needed to rinse it out. It was a PITA to get the foam off of the power head so I would often lift the whole thing off the top of the tube and then detach the foam to rinse it. This left the uplift tube open at the top. In addition, sometimes the power head would not easily come out of the uplift tube and I would end up pulling the tube out of the plate.

Between the opening at the top and the occasional opening into the plate, the two species managed to get down and under the plate. The whole set-up was somewhat jury rigged to accept the powerhead going into the top of the uplift tube.

But, as far as I am concerned a properly set up UGF or RUGF are great bio-filter media. I used to run a hang on with it when I ran it as an RUGF. The upward flow through the gravel prevented a lot of what would otherwise settle into the substrate instead to stay in the water. The hang on was set up for mechanical filtration and pretty much kept the water clean by removing the solid waste. I almost never had to vacuum that tank when I had that set up on it.

 

[Colin_T]

The above brings up a situation with my soon to be new tank build. I will be replacing a 20 gallon cube with a 21 gallon high. I've been waiting for being able to get fresh water scud cultures which just haven't been locally available this year. This could actually be a good thing as I'll be using UG filtration involving a couple of small power heads on 2 risers and another 2 air driven. Since I'll be using medium sized river pebbles as the substrate the scuds could easily establish colonies under the filter plates. It dawned on me that the power heads could pull scuds into the impellers which could disable their function. Since the scuds are so small they could possibly just pass through the impellers but seems to me that they could be an issue.

I don't think you need 2 powerheads and 2 airstones on an undergravel filter in a 20 gallon tank. To me that is overkill on an enormous scale. Especially if you plan on keeping slow moving crustaceans in the tank. I would run one or two airstones and leave it at that.

 

[jaylach]

I don't think you need 2 powerheads and 2 airstones on an undergravel filter in a 20 gallon tank. To me that is overkill on an enormous scale. Especially if you plan on keeping slow moving crustaceans in the tank. I would run one or two airstones and leave it at that.

The main fish would be Panda Garra and they like fast water. The power heads will not run full flow.

 

[GaryE]

Next, I do not agree with this. It is not a universal statement.
Have a look at the pictures on Planetcatfish of Hopisoma sp. (Cw111). You will see that the males get a rather long dorsal fin as adults. Below is one of the pics from there.

Long fins are well known in nature, as long finned fish. Longfins as a noun are a hobby creation, especially if you read the thread and realize at that point we were talking about Hoplisoma paleatum, which in nature has short fins. One of the fish I am considering for a UG filter has a high dorsal - Hoplisoma loretoensis. Check it out on Planet Catfish - it's pretty.
Misreads feed misunderstandings. The way everyone writes on the internet, a space that matters grammatically is easy to miss.

In that 21 gallon, I agree that it's too much, even with small powerheads. Amazon has some small and weak pumps, and they might be good, but I use air or single small powerheads in my 20s, with an HOB as well for current loving fish. I'm one for supposedly overfiltering tanks, and like my plan Bs. Also, it's so much easier to cycle an HOB in advance to buy time for the UG to get up to speed. You can always remove the HOB later if you change the set up for slow water fish.

Years ago I bought three homemade tanks second hand, and they came with homemade UG filters made out of pvc pipe. I used them, and the tanks were very stable (back in my test kit days) and allowed me to breed fish like Satanoperca - delicate ones. There was no plate, but a repeatedly partially cut set of pipes. These are what I've made as my fish crafting project. So I won't have creatures living under the plates. But it happens a lot with commercial ones - I had banjo cats move in under one and only come out every 6 months or so.

Fry in sumps, fry in UGs - I've even found young fish alive in Aquaclears.

I think we should bring back the undergravel filter. We still have the tools invented to keep them working, as standard gear (gravel vacuums), so we'd be all set. They worked in many applications. It's not like the father fish foolishness as an idea once sensibly rejected brought back - they aren't a thought experiment. It's an old tool that works. Nail guns work for some jobs, but hammers are good for others.

 

[Magnum Man]

I've also had critters living under plates... last for me was dwarf mexican cray's , and no filters are safe from critters moving in I repeatedly pull out small hillstream loaches from my hang on back filters, that go up the waterfall... at least with sponge filters there are no moving parts...

if something is living under your plate, it just becomes part of your living filter... I guess it could become a problem, if it's a baby that continues to grow, beyond the space available...

I have about a dozen of what I consider the best made plates, from the 80's just before they fell from grace... I would be running more of them if it weren't for the tubes becoming brittle, and me not being able to easily find replacements... maybe in retirement I'll have more time to search out the small parts for my plates... I had them in all my tanks, before I got out of them 30-40 years ago...

 

[GaryE]

It was the brittleness of the plastic that did in the commercial ones I had. They didn't last many years if exposed to air. And so, I make them.

 

[Colin_T]

I have about a dozen of what I consider the best made plates, from the 80's just before they fell from grace... I would be running more of them if it weren't for the tubes becoming brittle, and me not being able to easily find replacements... maybe in retirement I'll have more time to search out the small parts for my plates... I had them in all my tanks, before I got out of them 30-40 years ago...

We replaced broken uplift tubes with pvc pipe. You just cut a piece to go over the old broken uplift or replace the broken uplift with the pvc pipe. You can glue them to the filter plates or if you want to go extreme, get a fitting for the pvc pipe and glue the fitting over the hole, then put the pvc pipe in the fitting.

 

[jaylach]

In that 21 gallon, I agree that it's too much, even with small powerheads. Amazon has some small and weak pumps, and they might be good, but I use air or single small powerheads in my 20s, with an HOB as well for current loving fish. I'm one for supposedly overfiltering tanks, and like my plan Bs. Also, it's so much easier to cycle an HOB in advance to buy time for the UG to get up to speed. You can always remove the HOB later if you change the set up for slow water fish.

I'll stay with both power heads. They each can pull 127 GPH but I'll throttle them down to around 50 GPH to get my target of 5-6 water turnovers per hour.

 

[Back in the fold]

I used to have Corydoras years ago in my aquariums when I used under gravel filters and never had any problems with the catfish . Everybody else that had them had UGF’s with theirs too and no problems . I agree with @plebian . Corydoras are probably found in waters with every kind of bottom there is . This whole sand thing is just the newest fad in the hobby along with Betta’s only in ten gallons . One day it will change . Correct me if I’m wrong but what I think Gary’s wondering is if the substrate promotes harmful pathogens or bacteria that adversely affect the fish . I say probably not because a biological filter is supposed to right wrongs and keep the healthy balance . I see no difference in a nice gravel over under gravel filter plates and a sponge filter that fish peck at .

 

[TwoTankAmin]

Firstly, this thread was no about longfins of long fin, it was about keeping corys on a tank with an undergravel filter. Long fins were never mentioned until you brought it up.

GaryE you need to go back and reread this thread, It was never about paleatus, it was about corys. Nor when you typed your opinion that long fins were all man made you never mentioned any species specifically. If anybody needs to watch their language here, I think it is you.

No specific cory species was even mentioned until post #8 where magnum referred to sterbai in his picture in that reply.

You did not mention a species until post #9 which was your 4th post in this thread and you mentioned a number of species. Here is what you wrote in the middle of post #9 (bold added by me):

I have one farm raised member of the group, some paleatum, and another mixed group of raised from eggs and bought from store panda. All my others come from a supplier who orders direct from South America. I have concolor, brevirostre, atropersonatum, melini, grantii, arcuatum, napoensis, loretoensis and sodalis, and all except the sodalis and brevirostre are quite young.

Lower down in that post you also mentioned several more species:

Osteogaster aenea, our old friend the bronze Cory is a fish caught up in the defining what a species is debates scientifically, but which has a huge range. It has a temperature spread from 17c to 26. It seems to like around 20, but we keep it at 26 in tanks and pathogens and dangerous bacteria like that temp more than the fish do.

Hoplisoma paleatum, the salt and pepper Cory in some regions is the other most common Cory, and its natural ransge is 18 to 23 degrees.

Meanwhile, the popular Hoplisoma sterbai likes 26 to 30 degrees. It doesn't do well cooler.

Take a look what what the Google AI says on this subject. I know the AI can be way off but in this case it looks pretty accurate. Here is how it summarizes the terms after giving all the details:

Summary of differences

	Longfin	Long fin fish
Usage	A specific species, a family name, or a scientific classification	A descriptive term for a fish with elongated fins
Example	New Zealand longfin eel (Anguilla dieffenbachii)	Long-finned tetra (Brycinus longipinnis)
Context	Can be a noun for a specific type of fish	Often an adjective describing a physical characteristic
Examples	Longfin eel, Longfins (Plesiopidae)	Longfin betta, Longfin tiger barb

In short, "longfin" can be a proper noun referring to a specific fish or group, while "long fin fish" is a descriptive phrase for any fish that has long fins.

from HERE

And finally when you typed "Long fins are a mutation manipulated by line breeders on farms. For about 2-3 years when they were new, you couldn't get natural forms around here." you never once mentioned a species in that thread.

So I stand by what I wrote. Any species named a Longfin must also be a long finned fish. And I am unaware that the term, Longfin is a Latin term used in the identified name of any species of fish. The terms longfin and long fin or long finned are all descriptive terms.

Boris Gomelsky, Kyle J Schneider, Ahmed S Alsaqufi, Inheritance of Long Fins in Ornamental Koi Carp, North American Journal of Aquaculture, Volume 73, Issue 1, January 2011, Pages 49–52, https://doi.org/10.1080/15222055.2011.544942

Abstract​

Inheritance of long fins in ornamental koi carp Cyprinus carpio was studied. Fish segregations with regard to the presence or absence of long fins in two progenies were recorded and analyzed. In progeny 1, produced by crossing a long‐fin koi female with a short‐fin (wild‐type) koi male, the observed segregation of long‐fin fish : short‐fin fish did not differ significantly from the 1:1 Mendelian ratio. In progeny 2, produced by crossing the same long‐fin female with a long‐fin male, the observed segregation of long‐fin fish : short‐fin fish did not differ significantly from the 3:1 Mendelian ratio. Based on these data, it was concluded that the appearance of long fins in koi is under the control of a dominant mutation of one gene (Lf/lf). Fish with genotypes LfLf and Lflf have long fins, while fish with genotype lflf do not have this trait. Since the appearance of long fins in koi is controlled by a dominant mutation, the development of a true‐bred, long‐fin line could be achieved only by identifying heterozygotes Lflf by means of test crosses and removing them from the stock.