I hear that people rescue tortoises a great deal because people have no idea of what they will grow into. It doesn't surprise me that turtles also need rescuing.
Sulcata tortoises seem to be the biggest issue there. They easily grow to 100 pounds and need LOTS of room and a warm place to overwinter if in a colder climate. They're adorable as babies but start to get too large for most people in 5-10 years.
On the turtle front Red-Earred Sliders are the most abandoned. They start out the size of quarters but females grow to be 10"+ and males aren't much smaller. As a turtle needs roughly 10 gallons of water per inch of shell you can see the commitment the little baby hatchling will need when he/she is fully grown.
It seems like the best fish tank in the world and maybe like your wife did you a bit of a favor maybe?
That's debatable but I personally agree. They get to live as they would in the wild including full sunlight but have less predators. You do have to conscious of raccoons and herons though.
Dan,
Could you give a dimension for your tank?
Indoors we have a 40 gallon utility tub set up with a 6'x4' land enclosure for some semi-terrestrial turtles (a Reeves and two Wood), a 40 breeder for an African Sideneck, and a 55 gallon for our indoor fish (4 goldfish, some cory cats, another catfish (I'm not sure of the species but he's a forager-downward facing mouth), some otocinclus, and some apple snails).
The ponds outdoors are roughly:
Upper Setup:
Topmost retention basin-6'l x 6'w x ~18" average
Middle "bog"-12'l x ~5'w x average of 4" water over pea gravel
Lower pond-12'l x ~11'w x maybe 3' average depth (42" maximum, sharp slopes to the edges to deter herons
Lower setup:
Upper section-~12'l x ~5'w x ~12" average water depth
Lower section-~18'l x ~12'w x ~3' average depth (48" maximum, large shelf at 2')
New Frog pond:
~7'l x ~3'w x ~12" deep
I just built this today as the previous design for the total setup didn't work out and I was leaking in the stream connecting top to bottom. I couldn't locate where it was leaking so finally gave up and moved this piece of liner to give the frogs a better place to lay their eggs.
Note: I haven't finished this yet and it shows. This is definitely a work in progress (I did a fair share of this this summer) so keep this in mind.
On to the pictures:
View out of our door-
Closeup on the Copper Rose since my wife adores it so much-
Another angle from the corner of our sidewalk-
Same spot but looking toward the ponds-
Overall shot of the upper pond-
And a shot from the other side-
The top retention basin which filters water through floating plants-
Close up on some of those plants-
The middle "bog"-
Close up-
The bottom pond-
Shot of the waterfall-
Some of the fish-
Here's "Crackers" (our second turtle, who we rescued after our little gal "Soup") clearly visible at the bottom of the pond 3 1/2 feet deep. Crackers runs the show outside-
Onto the lower set of ponds. Here's a shot from uphill-
The upper piece flowing into the lower-
And the lower basin (this is where most of the turtles hang out and I'm letting it stay green to protect them and the fish as it has more shallow areas)-
"Cooter", our rescued Red-Bellied Cooter, was curious what I was doing-
The new frog pond I made today with the moved liner. Still have lots of work to do on this one-
Hope you enjoyed the tour.