This is your onestop shop for Chico Marx playing the piano
Here's the Movies, Songs and the character Chico plays in the film
0:00 The Cocoanuts (1929) "Gypsy Love Song" as Signor Pastrami the Lithuanian Pianist
1:57 Animal Crackers (1930) "Silver Threads Among the Gold" as Signor Emmanuel Ravelli
3:26 Monkey Business (1931) "Pizzicatto / When I Take My Sugar to Tea" as Chico
5:12 Horse Feathers (1932) "Collegiate" as Baravelli the piano teacher
6:33 A Night at the Opera (1935) "All I Do Is Dream Of You" as Fiorello
8:11 A Day at the Races (1937) "Hungarian Rhapsody #2" and "On The Beach at Bali Bali" as Tony
10:24 At The Circus (1939) "Beer Barrel Polka" as Antonio
12:08 Go West (1940) "The Woodpecker Song" as Joe Panello
14:03 The Big Store (1941) "Mamãe eu Quero" as Ravelli assisted by Harpo (in the film his name is Wacky)
16:57 Night In Casablanca (1946) "Hungarian Rhapsody #2," "Beer Barrel Polka," and "Moonlight Cocktail" as Corbaccio (PS I put the wrong date for Hungarian Rhapsody,,,should be 1847 not 1947)
There is also a duet with a violinist from the film Love Happy (1950) that has been posted on YouTube and it worth a look but I didn't include it because its not a solo